Mary and Ivan collect cards and stickers. Ivan has 55 less cards than stickers. Ivan has 3 times the number of cards Mary has, and Mary has 20% more stickers than Ivan. After Mary gives Ivan all of her cards and Ivan gives Mary 60% of his stickers, Ivan has 6 less stickers than cards. Find the number of stickers Mary has at first.

Mary		Ivan
Stickers	Cards	Stickers	Cards
3.6 u + 66	1 u	3 u + 55	3 u
+ 1.8 u + 33	- 1 u	- 1.8 u - 33	+ 1 u
5.4 u + 99	0	1.2 u + 22	4 u

100%+ 20% = 120% 

120% x 3 u
= ¹²⁰₁₀₀ x 3 u
= 3.6 u

120% x 55
= ¹²⁰₁₀₀ x 55
= 66 

60% x 3 u
= ⁶⁰₁₀₀ x 3 u
= 1.8 u  

60% x 55 
= ⁶⁰₁₀₀ x 55
= 33 

If another 6 stickers are given to Ivan, he will have equal number of stickers and cards in the end.
4 u = 1.2 u + 22 + 6
4 u - 1.2 u = 28
2.8 u = 28

1 u = 28 ÷ 2.8 = 10

Number of stickers that Mary has at first
= 3.6 u + 66
= 3.6 x 10 + 66
= 36 + 66
= 102
 
Answer(s): 102