There are 25% more pink cards than brown cards in a bag. After David removed 40% of the pink cards and increased the number of brown cards by 20%, there are now 108 fewer pink cards than brown cards. Find the number of brown cards at first.

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

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

125% = ¹²⁵₁₀₀ = ⁵₄

Number of pink cards that David removed
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u 
= 2 u

Number of brown cards that David increased 
= 20% x 4 u
= ²⁰₁₀₀  x 4 u
= 0.8 u

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

Number of brown cards in the end
= 4 u + 0.8 u
= 4.8 u

Number of fewer pink cards than brown cards in the end
= 4.8 u - 3 u 
= 1.8 u 

1.8 u = 108

1 u = 108 ÷ 1.8 = 60

Number of brown cards at first
= 4 u
= 4 x 60
= 240

Answer(s): 240