There are 25% more brown pens than purple pens in a bag. After Justin removed 20% of the brown pens and increased the number of purple pens by 35%, there are now 84 fewer brown pens than purple pens. Find the number of purple pens at first.

	Brown	Purple
Before	5 u	4 u
Change	- 1 u	+ 1.4 u
After	4 u	5.4 u

Number of brown pens in percentage
= 100% + 25%
= 125%

125% = ¹²⁵₁₀₀ = ⁵₄

Number of brown pens that Justin removed
= 20% x 5 u
= ²⁰₁₀₀ x 5 u 
= 1 u

Number of purple pens that Justin increased 
= 35% x 4 u
= ³⁵₁₀₀  x 4 u
= 1.4 u

Number of brown pens in the end
= 5 u - 1 u
= 4 u

Number of purple pens in the end
= 4 u + 1.4 u
= 5.4 u

Number of fewer brown pens than purple pens in the end
= 5.4 u - 4 u 
= 1.4 u 

1.4 u = 84

1 u = 84 ÷ 1.4 = 60

Number of purple pens at first
= 4 u
= 4 x 60
= 240

Answer(s): 240