40% of Dana's amount was $2668 less than Sean's amount. When Dana spent 30% of her amount and Sean spent 70% of his amount, they had the same amount of amount left. Find the amount that Sean had at first.

	Dana	Sean
Before	30 u	70 u
Change	- 9 u	- 49 u
After	21 u	21 u

Percentage of Dana's amount left
= 100% - 30%
= 70%

Percentage of Sean's amount left
= 100% - 70%
= 30%

70% = ⁷⁰₁₀₀ = ⁷₁₀
30% = ³⁰₁₀₀ = ³₁₀

The amounts of amount that Dana and Sean had left were the same. Make the numerators the same.

⁷₁₀ of Dana's amount = ³₁₀ of Sean's amount
²¹₃₀ of Dana's amount = ²¹₇₀ of Sean's amount

Amount that Dana had = 30 u

40% of the amount that Dana had
= 40% x 30 u
= ⁴⁰₁₀₀ x 30 u
= 12 u

Difference between Sean's amount and 40% of Dana's amount
= 70 u - 12 u
= 58 u

58 u = 2668

1 u = 2668 ÷ 58 = 46

Amount that Sean had at first
= 70 u
= 70 x 46
= $3220

Answer(s): $3220