[問題]GWD 12-29

[GuDon]

Q29:
Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?
(1) She bought $4.40 worth of stamps.
(2) She bought an equal number of $0.15 stamps and $0.29 stamps.

ans: A

我想請問各位大大
這題條件一除了用數字帶進去外還有別的方法嗎
因為怕考試的時候想不出來...

感謝大大們解惑喔