There are 25% more brown erasers than silver erasers in a bag. After Zeph removed 40% of the brown erasers and increased the number of silver erasers by 20%, there are now 198 fewer brown erasers than silver erasers. Find the number of silver erasers at first.

	Brown	Silver
Before	5 u	4 u
Change	- 2 u	+ 0.8 u
After	3 u	4.8 u

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

125% = ¹²⁵₁₀₀ = ⁵₄

Number of brown erasers that Zeph removed
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u 
= 2 u

Number of silver erasers that Zeph increased 
= 20% x 4 u
= ²⁰₁₀₀  x 4 u
= 0.8 u

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

Number of silver erasers in the end
= 4 u + 0.8 u
= 4.8 u

Number of fewer brown erasers than silver erasers in the end
= 4.8 u - 3 u 
= 1.8 u 

1.8 u = 198

1 u = 198 ÷ 1.8 = 110

Number of silver erasers at first
= 4 u
= 4 x 110
= 440

Answer(s): 440