There are 25% more grey erasers than white erasers in a bag. After Lee removed 20% of the grey erasers and increased the number of white erasers by 20%, there are now 56 fewer grey erasers than white erasers. Find the number of white erasers at first.

	Grey	White
Before	5 u	4 u
Change	- 1 u	+ 0.8 u
After	4 u	4.8 u

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

125% = ¹²⁵₁₀₀ = ⁵₄

Number of grey erasers that Lee removed
= 20% x 5 u
= ²⁰₁₀₀ x 5 u 
= 1 u

Number of white erasers that Lee increased 
= 20% x 4 u
= ²⁰₁₀₀  x 4 u
= 0.8 u

Number of grey erasers in the end
= 5 u - 1 u
= 4 u

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

Number of fewer grey erasers than white erasers in the end
= 4.8 u - 4 u 
= 0.8 u 

0.8 u = 56

1 u = 56 ÷ 0.8 = 70

Number of white erasers at first
= 4 u
= 4 x 70
= 280

Answer(s): 280