Problem Solving

VJesus12 wrote: ↑

Thu Apr 08, 2021 11:49 am

There were 36,000 hardback copies of a certain novel sold before the paperback version was issued. From the time the first paperback copy was sold until the last copy of the novel was sold 9 times as many paperback copies as hardback copies were sold. If a total of 441,000 copies of the novel were sold in all, how many paperback copies were sold?

A. 45,000
B. 360,000
C. 364,500
D. 392,000
E. 396,900

Answer: C

Source: Official Guide

From the time the first paperback copy was sold until the last copy of the novel was sold 9 times as many paperback copies as hardback copies were sold
Let x = number of hardback copies sold during this time
So 9x = number of paperback copies sold during this time
So, x + 9x = total number of copies sold DURING THIS TIME PERIOD

A total of 441,000 copies of the novel were sold in all
GIVEN: 36,000 hardback copies sold BEFORE the paperback version was issued.
So, we get: 36,000 + x + 9x = 441,000
Simplify: 36,000 + 10x = 441,000
We get: 10x = 405,000
Solve: x = 40,500
This also means 9x = 9(40,500) = 364,500

So, 364,500 paperback copies were

Answer: C

Cheers,
Brent