20% of Oscar's savings was $16 more than 40% of Michael's savings. After Oscar spent ³₁₀ of his savings and Michael spent 40% of his savings, Michael had $124 less than Oscar. How much was Michael's saving at first?

	Michael	Oscar
Before	5 u	10 u + 80
Change	- 2 u	- 3 u - 24
After	3 u	7 u + 56
Comparing Michael and Oscar in the end		124 more

20% = ²⁰₁₀₀ = ¹₅

40% = ⁴⁰₁₀₀ = ²₅

¹₅ Oscar = ²₅ Michael + 16 

Make the numerators the same. LCM of 1 and 2 is 2.
 
1x25x2 Oscar = 2x15x1 Michael + 16 
210 Oscar = 25 Michael + 16 

Simplify the fractions.
¹₁₀ Oscar = ¹₅ Michael + 8

Let ¹₅ Michael be 1 u.

Michael's savings at first = 5 u

¹₁₀ Oscar = ¹₅ Michael + 8
Let ¹₁₀ Oscar be 1 u + 8.

Oscar's savings at first
= 10 x (1 u + 8) 
= 10 u + 80

Savings that Michael spent
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u
= 2 u

Savings that Oscar spent 
= ³₁₀ x (10 u + 80)
= 3 u + 24 

Michael had $124 less than Oscar in the end. If another $124 was given to Michael, the amount that each had in the end would be the same.

7 u + 56 = 3 u + 124 
7 u - 3 u = 124 - 56
4 u = 68

1 u = 68 ÷ 4 = 17

Savings that Michael had at first
= 5 u 
= 5 x 17
= $85

Answer(s): $85