Free Scientific Reasoning MCQs with Answers

271. In a restaurant recently, I received the following bill: Starter $7.00 Main Course $20.75 Dessert $9.75 Drink $4.50 Service Charge $5.25 TOTAL $47.25 What percentage of the cost of the food and drink had been added to the bill as service charge?

• A. 11.1%
• B. 12.5%
• C. 14.0%
• D. 15.0%

Explanation: To find the percentage of the cost of food and drink that was added as a service charge, we need to first calculate the total cost of food and drink.Total cost of food and drink = $7.00 + $20.75 + $9.75 + $4.50 = $42.00Now, we can calculate the percentage of the cost of food and drink that was added as a service charge:Service charge percentage = (Service charge / Total cost of food and drink) x 100%Plugging in the values, we get:Service charge percentage = ($5.25 / $42.00) x 100% = 12.5%Therefore, the answer is B) 12.5%.

272. A recipe for tarte Tatin requires: 500g pastry 800g apples 100 g caster sugar 100 ml apple juice 6g of vanilla 50 g of butter Amber, Bekim, Cairo, and Darcy have the following quantities of each ingredient: The quantity is given in the image below Who can make the largest tarte Tatin?

• A. Amber
• B. Bekim
• C. Cairo
• D. Darcy

Explanation: Amber has enough Pastry to make 4 Tarte Tatin. Amber has enough Apples to make 4 Tarte Tatin. Amber has enough Caster Sugar to make 4 Tarte Tatin. Amber has enough Apple Juice to make 3 Tarte Tatin. Amber has enough Vanilla to make 4 Tarte Tatin. Amber has enough Butter to make 4 Tarte Tatin. The maximum number of Tarte Tatin that Amber can make is determined by the ingredient that allows the least complete portions, i.e. here Apple Juice is only enough for 3 Tarte Tatin, so Amber can make 3 Tarte Tatin in total. Bekim has enough Pastry to make 6 Tarte Tatin. Bekim has enough Apples to make 3 Tarte Tatin. Bekim has enough Caster Sugar to make 4 Tarte Tatin. Bekim has enough Apple Juice to make 5 Tarte Tatin. Bekim has enough Vanilla to make 3 Tarte Tatin. Bekim has enough Butter to make 2 Tarte Tatin. The maximum number of Tarte Tatin that Bekim can make is determined by the ingredient that allows the least complete portions, i.e. here Butter is only enough for 2 Tarte Tatin, so Bekim can make 2 Tarte Tatin in total. Cairo has enough Pastry to make 4 Tarte Tatin. Cairo has enough Apples to make 4 Tarte Tatin. Cairo has enough Caster Sugar to make 4 Tarte Tatin. Cairo has enough Apple Juice to make 2 Tarte Tatin. Cairo has enough Vanilla to make 2 Tarte Tatin. Cairo has enough Butter to make 4 Tarte Tatin. The maximum number of Tarte Tatin that Cairo can make is determined by the ingredient that allows the least complete portions, i.e. here Apple Juice and Vanilla are only enough for 2 Tarte Tatin, so Cairo can make 2 Tarte Tatin in total. Darcy has enough Pastry to make 5 Tarte Tatin. Darcy has enough Apples to make 1 Tarte Tatin. We do not need to calculate further because it is clear that Darcy cannot make more than 1 Tarte Tatin due to lack of apples. Therefore, the answer is A, Amber, as she can make the most Tarte Tatin with these ingredients

273. Many people were worried when they found that their photocopiers had been sometimes changing numbers; one photocopier sometimes, although not always, changed 6 into 8. A list of prices was copied on this photocopier. The first five prices on the copy·are shown below. $54.80 $60.00 $65.40 $70.80 $78.20 In the original list, the prices had increased by the same amount each time. What was the next price.on the original list?

• A. $81.60
• B. $81.80
• C. $83.60
• D. $85.60

Explanation: Since the photocopiers change the 6s to 8s, we can assume that the first price is $54.60 instead of $54.80, the third price is actually $65.40 instead of $85.40, and the fifth price is $76.20 instead of $78.20. Doing this means that we now have a consistent increase in prices of $5.40.With that, we can make our own copy of the original list:$54.60$60.00$65.40$70.80$76.20With another consistent price increase of $5.40, the next price on the original list = $76.20+$5.40=$81.60Therefore, the answer is A.

274. Mr and Mrs Porter drove down to see Sweeney. Mr Porter drove the first 20 km on the way there, and Mrs Porter drove the rest of the way. On the return journey, she drove the first 30 km and he drove the rest. How much farther did Mrs Porter drive than Mr Porter?

• A. No farther
• B. 10km
• C. 20 km
• D. There is not enough information to work it out

Explanation: Distance to sweeney = xMr. Porter drove 20 km on the initial journey, and (x-30) km on the return journey.Total distance Mr. Porter drove = 20 + x - 30 = (x-10) kmMrs. Porter drove (x-20) km on the initial journey, and 30 km on the return journey.Total distance Mrs. Porter drove = x - 20 + 30 = (x+10) kmDifference between total distance of Mrs. Porter and Mr. Porter=(x+10) - (x-10)= x + 10 - x + 10=20 kmTherefore, the answer is option C.

275. In an ecosystem, producers convert the sun's energy into a usable source for other organisms. Primary consumers eat the producers, secondary consumers eat primary consumers, and tertiary consumers eat secondary consumers.The lion is both a scavenger and a secondary consumer. Thus, they may fill more than one role in the ecosystem.If additional cheetahs were introduced into this ecosystem, shortly thereafter we would expect a decrease in the:

• A. lion population
• B. Hyena population
• C. Dung-rolling beetle population
• D. Hare population

Explanation: The "shortly thereafter" part of this question is very important in determining the answer. It means you have to look for the first and foremost effect an increase in the population of a certain organism would have i.e. a decrease in the population of its prey. Here, the Cheetah preys on Hare and Gazelle. Since Gazelle is not in the options, the answer would be D, Hare population. Option A is incorrect because even though the lion population will decrease, it will not decrease immediately. An increased number of Cheetahs means increased competition for Lions over their shared prey, Gazelle, which will lead to lesser food available for Lions causing a decrease in the Lion population. However, this is a more long term effect, and will not happen shortly thereafter as the lion also has other prey options available. Option B is also incorrect as the Hyena population will not decrease shortly after. Instead, it will increase shortly thereafter because less Hare means more grass will be available for Hyena to eat. Option C is incorrect because even though number of Hare are decreasing, the number of Cheetah have increased, which will balance out the amount of food available for them.

276. Which of the following is implied by the fact that seafloor spreading at the Mid-Atlantic Ridge is causing the Atlantic Ocean to widen by about 5 centimeters a year?

• A. The Mid-Atlantic Ridge is thousands of miles long.
• B. The Mid-Atlantic Ridge is the largest underwater structure in the Atlantic Ocean.
• C. The continents of North America and Europe are moving apart.
• D. The continents of North America and Europe are growing larger at the Mid-Atlantic Ridge.

Explanation: The correct answer is C. The fact that seafloor spreading at the Mid-Atlantic Ridge is causing the Atlantic Ocean to widen by about 5 centimeters a year implies that the continents of North America and Europe are moving apart. This is because the Mid-Atlantic Ridge is a divergent boundary where new crust is formed as tectonic plates move away from each other. As new crust is formed at the Mid-Atlantic Ridge, the ocean basin widens and the continents on either side are pushed farther apart.

277. A ballet dancer of mass 80 kg and a wingspan of 1m is executing a spin. She then folds her arms and brings them to within 20cm from the central axis of her body. If she was initially making 3 rotations per second, how many does she make now?

• A. 75
• B. 8/3
• C. 12
• D. 6

Explanation: By law of conservation of momenrum;Iiwi = Ifwf1/2 mr12 wi = 1/2 mr22 wfr12 wi = r22 wf12 *3 = 0.22 wf3 = 0.04 wfwf = 75 revolutions per second.

278. Twenty flies are placed in each of four glass tubes. The tubes are sealed. Tubes I and II are partially covered with black paper; Tubes III and IV are not covered. The tubes are placed as shown. Then they are exposed to blue light for five minutes. The number of flies in the uncovered part of each tube is shown in the drawing respond to;

• A. blue light but not gravity
• B. gravity but not blue light
• C. both blue light and gravity
• D. neither blue light nor gravity

Explanation: Comparing tubes III and IV, we can see that when there was a height difference in tube III, there were more flies in the upper half (19) than in the lower half (1). Meanwhile when tube IV was examined, the left and right halves - which were at the same height - had an equal number of flies(10). This shows that the flies did indeed respond to gravity. When we compare tubes II and IV, both of these are horizontally placed but in tube II, one half is covered with black paper while the other half is exposed to blue light. As a result, there are 18 flies in the exposed region and 2 in the darkened region. When this is compared to tube IV which had an equal number of flies in either half, we can conclude that exposure to blue light is detected by and responded to by the flies.

279. Why is the pupil of the human eye black?

• A. The pupil is made up of proteins that are pigmented to appear to give a black appearance
• B. The pupil can be of any color, not necessarily black
• C. The pupil is a hole that allows light to enter but the light is either absorbed or diffused within the eye before it can exit
• D. The vitreous humor behind the pupil is black in color which gives the transparent pupil a black appearance

Explanation: The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil.

280. Susan (circle), Ahmad (triangle), and Sam (star) are each walking in an octagonal park on a Sunday morning. At 10:00, the following figure depicts their positions. Susan moves 3 vertices clockwise in each hour, Ahmad moves 1 vertex clockwise each hour, while Sam moves 2 vertices anticlockwise each hour. Will all three ever meet on a vertex at the same instant?

• A. Yes, they meet at 12:00
• B. Yes, they meet at 15:00
• C. Yes, they meet at 17:00
• D. No, they never meet

Explanation: Given the movements in the question, following is the state after 5 hours (15:00)