Abi and Riordan collect erasers and beads. Riordan has 80 less erasers than beads. Riordan has 4 times the number of erasers Abi has, and Abi has 20% more beads than Riordan. After Abi gives Riordan all of her erasers and Riordan gives Abi 60% of his beads, Riordan has 2 less beads than erasers. Find the number of beads Abi has at first.

Abi		Riordan
Beads	Erasers	Beads	Erasers
4.8 u + 96	1 u	4 u + 80	4 u
+ 2.4 u + 48	- 1 u	- 2.4 u - 48	+ 1 u
7.2 u + 144	0	1.6 u + 32	5 u

100%+ 20% = 120% 

120% x 4 u
= ¹²⁰₁₀₀ x 4 u
= 4.8 u

120% x 80
= ¹²⁰₁₀₀ x 80
= 96 

60% x 4 u
= ⁶⁰₁₀₀ x 4 u
= 2.4 u  

60% x 80 
= ⁶⁰₁₀₀ x 80
= 48 

If another 2 beads are given to Riordan, he will have equal number of beads and erasers in the end.
5 u = 1.6 u + 32 + 2
5 u - 1.6 u = 34
3.4 u = 34

1 u = 34 ÷ 3.4 = 10

Number of beads that Abi has at first
= 4.8 u + 96
= 4.8 x 10 + 96
= 48 + 96
= 144
 
Answer(s): 144