Carl had a total of 200 notes. The notes are $2 notes and $10 notes. After he spent 90% of the $2 notes and 80% of the $10 notes on one vacuum cleaner, he was left with 3 times as many $10 notes as $2 notes. How much did the vacuum cleaner cost?

	$2	$10
Before	10x1 = 10 u	5x3 = 15 u
Change	- 9x1 = - 9 u	- 4x3 = - 12 u
After	1x1 = 1 u	1x3 = 3 u
Comparing $2 and $10 in the end	1x1  = 1 u	3x1 = 3 u

90% of $2 notes = ⁹⁰
₁₀₀ of $2 notes = ⁹₁₀ of $2 notes
80% of $10 notes = ⁸⁰₁₀₀ of $10 notes = ⁴₅ of $10 notes

The number of $2 notes in the end is repeated.  Make the number of $2 notes the same.  LCM of 1 and 3 is 3.

The number of $10 notes in the end is repeated. Make the number of $10 notes the same. LCM of 1 and 1 is 1.

Number of notes at first
= 10 u + 15 u
= 25 u

25 u = 200

1 u = 200 ÷ 25 = 8

	$2	$10
Number	9 u	12 u
Value	2	10
Total value	18 u	120 u

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

Value of $10 spent
= 12 u x 10
= 120 u

Price of the vacuum cleaner
= 18 u + 120 u
= 138 u
= 138 x 8
= $1104

Answer(s): $1104