Winnie had a total of 84 pieces of $50 and $20 notes at first. She spent ³₇ of the number of $50 notes and received another 4 pieces of $20 notes from her mother. After that, the number of $20 notes she had was ¹₂ of the remaining notes. How much money did Winnie have at first?

	$50	$20	Total
Before	7 u	4 u - 4	84
Change	- 3 u	+ 4
After	4 u
Comparing $50-notes and $20-notes	1x4 = 4 u	1x4 = 4 u

The number of $50-notes and $20-notes in the end is the same.

The number of $50-notes in the end is repeated.  Make the number of $50-notes in the end the same. LCM of 1 and 4 is 4.

Number of notes at first
= 7 u + 4 u - 4
= 11 u - 4

11 u - 4 = 84
11 u = 84 + 4
11 u = 88

1 u = 88 ÷  11 = 8

Number of $50-notes at first
= 7 u
= 7 x 8
= 56

Total value of $50-notes at first
= 56 x 50
= $2800

Number of $20-notes at first
= 4 u - 4
= 4 x 8 - 4
= 32 - 4
= 28

Total value of $20-notes at first
= 28 x 20
= $560

Amount that Winnie had at first
= 2800 + 560 
= $3360

Answer(s): $3360