A bookstore that sells used books sells each of its paperback books for a certain price and each of its hardcover books

[Gmat_mission]

A bookstore that sells used books sells each of its paperback books for a certain price and each of its hardcover books for a certain price. If Joe, Maria, and Paul bought books in this store, how much did Maria pay for 1 paperback book and 1 hardcover book?

(1) Joe bought 2 paperback books and 3 hardcover books for $12.50.
(2) Paul bought 4 paperback books and 6 hardcover books for $25.00.

Answer: E

Source: GMAT Prep

[deloitte247]

Target question => if Joe, Maria and Paul bought books in this store, how much did Maria pay for 1 paperback book and 1 hardcover book
Let the price of 1 paperback = p
Let the price of 1 hardcover = h
Find p+h


Statement 1 => Joe bought 2 paperback books and 3 hardcover books for $12.50
2p + 3h = 12.50
The exact value of p+h is unknown so the target question cannot be evaluated. Statement 1 is NOT SUFFICIENT


Statement 2 => Paul bought 4 paperback books and 6 hardcover books for $25.00
i.e 4p + 6h = 100
The exact value of p and h is unknown so the target question cannot be evaluated. Statement 2 is NOT SUFFICIENT


Combining both statements together =>
From statement 1 => 2p + 3h = 12.50
From statement 2 => 4p + 6h = 25.00
Divide statement 2 by 2
4p/2 + 6h/2 = 25.00/2
=> 2p + 3h = 12.50
This is the same as that of statement 1, no new expression was formed, hence, the value of p+h cannot be evaluated.


Both statements combined together are NOT SUFFICIENT
Answer = E