Carl had a total of 175 notes. The notes are $5 notes and $2 notes. After he spent 90% of the $5 notes and 60% of the $2 notes on one gas stove, he was left with 3 times as many $2 notes as $5 notes. How much did the gas stove cost?

	$5	$2
Before	10x2 = 20 u	5x3 = 15 u
Change	- 9x2 = - 18 u	- 3x3 = - 9 u
After	1x2 = 2 u	2x3 = 6 u
Comparing $5 and $2 in the end	1x2  = 2 u	3x2 = 6 u

90% of $5 notes = ⁹⁰
₁₀₀ of $5 notes = ⁹₁₀ of $5 notes
60% of $2 notes = ⁶⁰₁₀₀ of $2 notes = ³₅ of $2 notes

The number of $5 notes in the end is repeated.  Make the number of $5 notes the same.  LCM of 2 and 3 is 6.

The number of $2 notes in the end is repeated. Make the number of $2 notes the same. LCM of 1 and 2 is 2.

Number of notes at first
= 20 u + 15 u
= 35 u

35 u = 175

1 u = 175 ÷ 35 = 5

	$5	$2
Number	18 u	9 u
Value	5	2
Total value	90 u	18 u

Value of $5 spent
= 18 u x 5
= 90 u

Value of $2 spent
= 9 u x 2
= 18 u

Price of the gas stove
= 90 u + 18 u
= 108 u
= 108 x 5
= $540

Answer(s): $540