There are 25% more silver erasers than yellow erasers in a bag. After Paul removed 40% of the silver erasers and increased the number of yellow erasers by 10%, there are now 112 fewer silver erasers than yellow erasers. Find the number of yellow erasers at first.

	Silver	Yellow
Before	5 u	4 u
Change	- 2 u	+ 0.4 u
After	3 u	4.4 u

Number of silver erasers in percentage
= 100% + 25%
= 125%

125% = ¹²⁵₁₀₀ = ⁵₄

Number of silver erasers that Paul removed
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u 
= 2 u

Number of yellow erasers that Paul increased 
= 10% x 4 u
= ¹⁰₁₀₀  x 4 u
= 0.4 u

Number of silver erasers in the end
= 5 u - 2 u
= 3 u

Number of yellow erasers in the end
= 4 u + 0.4 u
= 4.4 u

Number of fewer silver erasers than yellow erasers in the end
= 4.4 u - 3 u 
= 1.4 u 

1.4 u = 112

1 u = 112 ÷ 1.4 = 80

Number of yellow erasers at first
= 4 u
= 4 x 80
= 320

Answer(s): 320