Carl had a total of 100 notes. The notes are $2 notes and $5 notes. After he spent 90% of the $2 notes and 60% of the $5 notes on one toaster oven, he was left with 4 times as many $5 notes as $2 notes. How much did the toaster oven cost?

	$2	$5
Before	10x1 = 10 u	5x2 = 10 u
Change	- 9x1 = - 9 u	- 3x2 = - 6 u
After	1x1 = 1 u	2x2 = 4 u
Comparing $2 and $5 in the end	1x1  = 1 u	4x1 = 4 u

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

The number of $2 notes in the end is repeated.  Make the number of $2 notes the same.  LCM of 2 and 4 is 4.

The number of $5 notes in the end is repeated. Make the number of $5 notes the same. LCM of 1 and 1 is 1.

Number of notes at first
= 10 u + 10 u
= 20 u

20 u = 100

1 u = 100 ÷ 20 = 5

	$2	$5
Number	9 u	6 u
Value	2	5
Total value	18 u	30 u

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

Value of $5 spent
= 6 u x 5
= 30 u

Price of the toaster oven
= 18 u + 30 u
= 48 u
= 48 x 5
= $240

Answer(s): $240