Yoko had a total of 120 pieces of $10 and $50 notes at first. She spent ⁵₈ of the number of $10 notes and received another 12 pieces of $50 notes from her mother. After that, the number of $50 notes she had was ¹₂ of the remaining notes. How much money did Yoko have at first?

	$10	$50	Total
Before	8 u	3 u - 12	120
Change	- 5 u	+ 12
After	3 u
Comparing $10-notes and $50-notes	1x3 = 3 u	1x3 = 3 u

The number of $10-notes and $50-notes in the end is the same.

The number of $10-notes in the end is repeated.  Make the number of $10-notes in the end the same. LCM of 1 and 3 is 3.

Number of notes at first
= 8 u + 3 u - 12
= 11 u - 12

11 u - 12 = 120
11 u = 120 + 12
11 u = 132

1 u = 132 ÷  11 = 12

Number of $10-notes at first
= 8 u
= 8 x 12
= 96

Total value of $10-notes at first
= 96 x 10
= $960

Number of $50-notes at first
= 3 u - 12
= 3 x 12 - 12
= 36 - 12
= 24

Total value of $50-notes at first
= 24 x 50
= $1200

Amount that Yoko had at first
= 960 + 1200 
= $2160

Answer(s): $2160