Question

Hector spent $33.20 at the post office. He bought 4 times as many 41-cent stamps as 2-cent stamps. How many of each did he buy?

Answer 1

Let x be the number of 2-cent stamps. We know that the 41-cents stamp are four times as many, so they are 4x. The total is thus worth

$0.02x + 0.41\cdot 4x = 33.20 \iff 0.02x + 1.64x = 33.20 \iff 1.66x = 33.20 \iff x = \dfrac{33.20}{1.66} = 20$

So, Hector bought 20 2-cents stamps, and 80 41-cents stamp.