Question

Mrs. martinez has $10,000 to invest.One bank offers her a return of 7.5% on the whole sum. Another bank offers her a return of 8% on part of the sum, and 6% on the rest of the sum. How much of the $10,000 would need to be invested at 8% at the second bank, for the overall to be the same as at the first bank?

Answer 1

we want to know when

.075*10000 = .08x + .06(10000-x)
x = 7500

Answer 2

.075*10000 = .08x + .06(10000-x)

x = 7500
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.075*10000 = .08*7500 + .06(10000-7500)
.075*10000 = 600 + .06(2500)
.075*10000 = 600 + 150
.075*10000 = 750

750$