Question 159527

Let x=amount of time it takes to complete 38 books
Now what we are going to be shooting for is the following:
(Rate at which we complete books)*x hours=38 books

Older printer prints at the rate of 1/3 book per hour
Newer printer prints at the rate of 1/(1 1/3) or 3/4 book per hour
Nephew tears up books at the rate of 1/6 book per hour
With all three working together, they work at the rate of:
1/3 + 3/4 - 1/6 or
4/12 + 9/12 -2/12=11/12 book per hour. So our equation to solve is:

(11/12)x=38  multiply each side by 12
11x=456 divide each side by 11
x=41.45hrs or 41hr 27min

CK
In 41.45 hours, old printer prints(1/3)(41.45)=13.82 books
In 41.45 hours, new printer prints (3/4)(41.45)=31.09 books
In 41.45 hours, nephew tears up (1/6)(41.45)=6.91 books
13.82 + 31.09 -6.91=38
38=38

Hope this helps---ptaylor