Nathan's total allowance is $11.25 ; amount deposited is $8.75
Given:
Savings = 7/9 of his allowance
Excess = $2.50 or 2/9 of his allowance
to get the amount deposited, we need to first get the total allowance.
2.50 ÷ 2/9 ⇒ 2.50 * 9/2 = 22.5/2 = 11.25
Total allowance = 11.25
amount to be deposited: 11.25 * 7/9 = 78.75/9 = 8.75