Carl had a total of 225 notes. The notes are $10 notes and $5 notes. After he spent 80% of the $10 notes and 60% of the $5 notes on one stand mixer, he was left with 3 times as many $5 notes as $10 notes. How much did the stand mixer cost?

	$10	$5
Before	5x2 = 10 u	5x3 = 15 u
Change	- 4x2 = - 8 u	- 3x3 = - 9 u
After	1x2 = 2 u	2x3 = 6 u
Comparing $10 and $5 in the end	1x2  = 2 u	3x2 = 6 u

80% of $10 notes = ⁸⁰
₁₀₀ of $10 notes = ⁴₅ of $10 notes
60% of $5 notes = ⁶⁰₁₀₀ of $5 notes = ³₅ of $5 notes

The number of $10 notes in the end is repeated.  Make the number of $10 notes the same.  LCM of 2 and 3 is 6.

The number of $5 notes in the end is repeated. Make the number of $5 notes the same. LCM of 1 and 2 is 2.

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

25 u = 225

1 u = 225 ÷ 25 = 9

	$10	$5
Number	8 u	9 u
Value	10	5
Total value	80 u	45 u

Value of $10 spent
= 8 u x 10
= 80 u

Value of $5 spent
= 9 u x 5
= 45 u

Price of the stand mixer
= 80 u + 45 u
= 125 u
= 125 x 9
= $1125

Answer(s): $1125