A mechanic services 4 cars in 8 hours. If he gets help from an assistant who works at 75% his rate, how many cars in 8 hours together?
Correct answer: D. 7
- A. 5.5
- B. 6
- C. 6.5
- D. 7
Explanation
The mechanic services 4 cars in 8 hours, equating to a rate of 0.5 cars per hour. The assistant, working at 75% of the mechanic's rate, services 0.75 * 0.5 = 0.375 cars per hour. Together, their combined rate is 0.5 + 0.375 = 0.875 cars per hour. Over 8 hours, they can service 8 * 0.875 = 7 cars. Hence, Option D is correct. Option A underestimates, Option B assumes a lower contribution from the assistant, and Option C miscalculates the combined output.
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