Salik had 50% more pens than Aaron. Christian had 20% fewer pens than Salik. Salik and Aaron gave Christian some pens in the ratio of 4 : 5. As a result, Christian had 25% more pens than before. Given that Christian had 240 more pens than Aaron in the end, how many pens did Salik give to Christian?

Salik	Aaron	Christian
3x5	2x5
5x3		4x3
15	10	12

100% + 50% = 150%
150% = ¹⁵⁰₁₀₀ = ³₂

Salik : Aaron = 3 : 2

100% - 20% = 80%
80% = ⁸⁰₁₀₀ = ⁴₅

Salik : Christian = 5 : 4

The number of pens that Salik had at first is repeated. Make the number of pens that Salik had at first the same.  LCM of 3 and 5 is 15.

	Salik	Aaron	Christian
Before	15x3 =  45 u	10x3 = 30 u	12x3 = 36 u
Change			+ 3x3 = + 9 u
Comparing the changes in the number of pens	- 4x1 = - 4 u	- 5x1 = - 5 u	+ 9x1 = + 9 u
After	41 u	25 u	15x3 = 45 u

25% x 12 
= ²⁵₁₀₀ x 12 
= 3 

The total number of pens that Salik and Aaron gave to Christian is repeated.  Make the total number of pens that Salik and Aaron gave to Christian the same.  LCM of 9 and 3 is 9.

Number of pens that Christian had more than Aaron 
= 45 u - 25 u
= 20 u

20 u = 240

1 u = 240 ÷ 20 = 12

Number of pens that Salik gave to Christian
= 4 u
= 4 x 12
= 48

Answer(s): 48