Amateur wrote:
Danny purchased a number of grease pumps of only two possible variants: $5 pumps and $25 pumps. If the ratio between the number of $5 pumps purchased and the number of $25 pumps purchased is 13:7, How many $5 grease pumps did Danny buy?
(1) The total purchase price of the grease pumps Danny bought was less than $400 .
(2) The total purchase price of the grease pumps Danny bought was greater than $200.
Source: HULT
nice question!
suppose we have x pumps that cost 5$ and y pumps that cost 25$.
Danny then spent 5x+25y dollars on the pumps.
we also know that the ratio of x to y is 13:7.
minimum we can have is 13 x pumps and 7 y pumps.
13*5$ = 65$
7*25 = 175$
so minimum spent 240$.
1. total purchase price is less than 400$. only 1 option works... B, C, and E are out.
2. we can have various options...we can have x=13, y=7, or x=26, y=14, etc. not sufficient. D is out.
A is the answer.