There are 25% more pink stamps than yellow stamps in a bag. After Vincent removed 40% of the pink stamps and increased the number of yellow stamps by 30%, there are now 110 fewer pink stamps than yellow stamps. Find the number of yellow stamps at first.

	Pink	Yellow
Before	5 u	4 u
Change	- 2 u	+ 1.2 u
After	3 u	5.2 u

Number of pink stamps in percentage
= 100% + 25%
= 125%

125% = ¹²⁵₁₀₀ = ⁵₄

Number of pink stamps that Vincent removed
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u 
= 2 u

Number of yellow stamps that Vincent increased 
= 30% x 4 u
= ³⁰₁₀₀  x 4 u
= 1.2 u

Number of pink stamps in the end
= 5 u - 2 u
= 3 u

Number of yellow stamps in the end
= 4 u + 1.2 u
= 5.2 u

Number of fewer pink stamps than yellow stamps in the end
= 5.2 u - 3 u 
= 2.2 u 

2.2 u = 110

1 u = 110 ÷ 2.2 = 50

Number of yellow stamps at first
= 4 u
= 4 x 50
= 200

Answer(s): 200