There are 25% more red marbles than pink marbles in a bag. After Mark removed 40% of the red marbles and increased the number of pink marbles by 35%, there are now 96 fewer red marbles than pink marbles. Find the number of pink marbles at first.

	Red	Pink
Before	5 u	4 u
Change	- 2 u	+ 1.4 u
After	3 u	5.4 u

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

125% = ¹²⁵₁₀₀ = ⁵₄

Number of red marbles that Mark removed
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u 
= 2 u

Number of pink marbles that Mark increased 
= 35% x 4 u
= ³⁵₁₀₀  x 4 u
= 1.4 u

Number of red marbles in the end
= 5 u - 2 u
= 3 u

Number of pink marbles in the end
= 4 u + 1.4 u
= 5.4 u

Number of fewer red marbles than pink marbles in the end
= 5.4 u - 3 u 
= 2.4 u 

2.4 u = 96

1 u = 96 ÷ 2.4 = 40

Number of pink marbles at first
= 4 u
= 4 x 40
= 160

Answer(s): 160