A can complete a job in 10 days and B in 15 days. Working together, how many days will they take?
Correct answer: B. 6 days
- A. 5 days
- B. 6 days
- C. 8 days
- D. 12 days
Explanation
Work with rates, not days. A does 1/10 of the job per day and B does 1/15. Together they do 1/10 + 1/15 = 3/30 + 2/30 = 5/30 = 1/6 per day, so the job takes 6 days.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Time and Work
Problems measure work through rates, treating each person's or machine's contribution as work completed per unit time. Questions cover combined work, efficiency, wages, alternate working schedules, pipes and cisterns, and men-days relationships, with care needed to distinguish time taken by one worker from the time required when workers act together.
Practise Arithmetic
1,060 free Arithmetic MCQs from Mathematics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Mathematics questions like this
Mathematics is on 75 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Time and Work questions
A man's basic pay for a 40 hour week is Rs. 20 overtime is paid for at 25 % above the basic rate, in a certain week he worked overtime and his total wage was Rs. 25. He therefore worked for a total of:________?
P and Q can complete a work in 15 days and 10 days respectively. They started the work together and then Q left after 2 days. P alone completed the remaining work. The work was finished in__________days.
A and B can finish a work 30 days if they work together. They worked together for 20 days and then B left. A finished the remaining work in another 20 days. In how many days A alone can finish the work?
A is thrice as good as B in work. A is able to finish a job in 60 days less than B. They can finish the work in___________days if they work together.