Audrey bought 25% more stamps than Jonathan. Anna bought 20% fewer stamps than Audrey. Audrey and Jonathan gave Anna some stamps in the ratio 3 : 2. As a result, Anna had twice as much stamps as before. Given that Jonathan had 18 more stamps than Audrey in the end, how much stamps did Anna receive?

	Audrey	Jonathan	Anna
	5x5	4x5
	5x5		4x5
Before	25 u	20 u	20 u
Change			+ (2 x 20 u) = + 40 u
	- 3x8 = - 24 u	- 2x8 = - 16 u	+ 5x8 =  + 40 u
After	1 u	4 u	60 u

100% + 25% = 125%
125% = ¹²⁵₁₀₀ = ⁵₄

100% - 20% = 80%
80% = ⁸⁰₁₀₀ = ⁴₅

The number of stamps that Audrey had at first is the repeated identity.
LCM of 5 and 5 = 25

The change in the number of stamps that Anna had is the repeated identity when Audrey and Jonathan gave to Anna.
LCM of 40 and 5 = 40

Number of stamps that Jonathan had more than Audrey in the end
= 4 u - 1 u
= 3 u

3 u = 18
1 u = 18 ÷ 3 = 6

Number of stamps that Anna received
= 24 u + 16 u
= 40 u
= 40 x 6
= 240

Answer(s): 240