Question

If it takes a window washer 90 minutes to clean 11 windows, how long will it take to wash 55 windows at this rate? A. 6.72 hours B. 7.00 hours C. 7.50 hours D. 8.25 hours​

Answer 1

C. 7.50 hrs

Explanation:

Since it takes 90 mins to clean 11 windows, the rate that it takes the washer per window is
`(90)/(11)` minutes. At this rate, if he were to clean 55 windows it would take him
`(90)/(11)(55) = 450` minutes. This translates into 7.50 hrs.