Tiffany and Vincent collect pencils and erasers. Vincent has 100 more erasers than pencils. Vincent has 2 times the number of pencils Tiffany has, and Tiffany has 40% more erasers than Vincent. After Tiffany gives Vincent all of her pencils and Vincent gives Tiffany 70% of his erasers, Vincent has 6 more pencils than erasers. Find the number of erasers Tiffany has at first.

Tiffany		Vincent
Erasers	Pencils	Erasers	Pencils
2.8 u + 140	1 u	2 u + 100	2 u
+ 1.4 u + 70	- 1 u	- 1.4 u - 70	+ 1 u
4.2 u + 210	0	0.6 u + 30	3 u

100% + 40% = 140% 

140% x 2 u
= ¹⁴⁰₁₀₀ x 2 u
= 2.8 u

140% x 100
= ¹⁴⁰₁₀₀ x 100
= 140 

70% x 2 u
= ⁷⁰₁₀₀ x 2 u
= 1.4 u  

70% x 100 
= ⁷⁰₁₀₀ x 100
= 70 

If another 6 erasers are given to Vincent, he will have equal number of erasers and pencils in the end.
3 u = 0.6 u + 30 + 6
3 u - 0.6 u = 36
2.4 u = 36

1 u = 36 ÷ 2.4 = 15

Number of erasers that Tiffany has at first
= 2.8 u + 140
= 2.8 x 15 + 140
= 42 + 140
= 182
 
Answer(s): 182