90% of Tiffany's amount was $1188 more than John's amount. When Tiffany spent 55% of her amount and John spent 20% of his amount, they had the same amount of amount left. Find the amount that John had at first.

	90% of Tiffany's amount	Tiffany's amount	John's amount
Before	72 u	80 u	45 u
Change		- 44 u (- 55%)	- 9 u (- 20%)
After		36 u	36 u

Percentage of Tiffany's amount left
= 100% - 55%
= 45%

Percentage of John's amount left
= 100% - 20%
= 80%

45% = ⁴⁵₁₀₀ = ⁹₂₀
80% = ⁸⁰₁₀₀ = ⁴₅

The amounts of amount that Tiffany and John had left were the same.
Make the numerators the same.

⁹₂₀ of Tiffany's amount = ⁴₅ of John's amount
³⁶₈₀ of Tiffany's amount = ³⁶₄₅ of John's amount

Amount that Tiffany had = 80 u

90% of the amount that Tiffany had
= 80 u x 90%
= 80 u x ⁹⁰₁₀₀
= 72 u

Difference between 90% of Tiffany's amount and John's amount
= 72 u - 45 u 
= 27 u

27 u = 1188
1 u = 1188 ÷ 27 = 44

Amount that John had at first
= 45 u
= 45 x 44
= $1980

Answer(s): $1980