20% of Owen's savings was $10 more than 40% of Andy's savings. After Owen spent ³₁₀ of his savings and Andy spent 40% of his savings, Owen had $47 more than Andy. How much was Owen's saving at first?

	Andy	Owen
Before	5 u	10 u + 50
Change	- 2 u	- 3 u - 15
After	3 u	7 u + 35
Comparing Andy and Owen in the end		47 more

20% = ²⁰₁₀₀ = ¹₅

40% = ⁴⁰₁₀₀ = ²₅

¹₅ Owen = ²₅ Andy + 10 

Make the numerators the same. LCM of 1 and 2 is 2.
 
1x25x2 Owen = 2x15x1 Andy + 10 
210 Owen = 25 Andy + 10 

Simplify the fractions.
¹₁₀ Owen = ¹₅ Andy + 5

Let ¹₅ Andy be 1 u.

Andy's savings at first = 5 u

¹₁₀ Owen = ¹₅ Andy + 5
Let ¹₁₀ Owen be 1 u + 5.

Owen's savings at first
= 10 x (1 u + 5) 
= 10 u + 50

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

Savings that Owen spent 
= ³₁₀ x (10 u + 50)
= 3 u + 15 

Owen had $47 more than Andy in the end. If another $47 was given to Andy, the amount that each had in the end would be the same.

7 u + 35 = 3 u + 47 
7 u - 3 u = 47 - 35
4 u = 12

1 u = 12 ÷ 4 = 3

Savings that Owen had at first
= 10 u + 50
= 10 x 3 + 50
= 30 + 50
= $80

Answer(s): $80