Question

Bob can shave a cat in 3 hours; Fred can do it in 4 hours. If they work together without wasting a ton of time like they always do, how long will it take to shave the cat?

Answer 1

The answer to your question is 1 5/7 or 1.7 hours ≈ 1:43 min

Explanation:

Data

Bob lasts 3 hours

Fred lasts 4 hours

Together = ?

Process

1.- Determine what they do in 1 hour

Bob = 1/3 in x hours x/3

Fred = 1/4 in x hours x/4

2.- Write the equation to this problem

x/3 + x/4 = 1

3.- Solve it for x

(4x + 3x)/12 = 1

7x = 12

x = 12/7

x = 1 5/7 or 1.7 hours ≈ 1:43 min