There are 25% more yellow marbles than pink marbles in a bag. After Albert removed 20% of the yellow marbles and increased the number of pink marbles by 30%, there are now 60 fewer yellow marbles than pink marbles. Find the number of pink marbles at first.

	Yellow	Pink
Before	5 u	4 u
Change	- 1 u	+ 1.2 u
After	4 u	5.2 u

Number of yellow marbles in percentage
= 100% + 25%
= 125%

125% = ¹²⁵₁₀₀ = ⁵₄

Number of yellow marbles that Albert removed
= 20% x 5 u
= ²⁰₁₀₀ x 5 u 
= 1 u

Number of pink marbles that Albert increased 
= 30% x 4 u
= ³⁰₁₀₀  x 4 u
= 1.2 u

Number of yellow marbles in the end
= 5 u - 1 u
= 4 u

Number of pink marbles in the end
= 4 u + 1.2 u
= 5.2 u

Number of fewer yellow marbles than pink marbles in the end
= 5.2 u - 4 u 
= 1.2 u 

1.2 u = 60

1 u = 60 ÷ 1.2 = 50

Number of pink marbles at first
= 4 u
= 4 x 50
= 200

Answer(s): 200