If 4 workers can assemble a car in 6 hours, how long would it take 15 workers to assemble the same car?

Question: If 4 workers can assemble a car in 6 hours, how long would it take 15 workers to assemble the same car?

Solution:
Given,
4 workers can assemble a car in 6 hours
∴ 1 workers can assemble a car in (6 × 4) hours
∴ 15 workers can assemble a car in (24/15) hours
= (24 × 60)/15 minutes
= 96 minutes