Question

A man invests 16,500 pesos in two kinds treasury notes, which yield 7.5% and 6% annually. After two years year, he earns 2,442 pesos in interest. How much does he invest at the 6 % rate?

Answer 1

Let "x" be the amount invested at 6% rate.

Then, the amount invested in 7.5% account is

= 16500 - x

Given : After two years, total interest earned in both the accounts is $2,442.

So, we have

Interest at 6% rate + Interest at 7.5% rate = 2442

x ⋅ 6/100 ⋅ 2 + (16500 - x) ⋅ 7.5/100 ⋅ 2 = 2442

x ⋅ 0.06 ⋅ 2 + (16500 - x) ⋅ 0.075 ⋅ 2 = 2442

0.12x + (16500 - x) ⋅ 0.15 = 2442

0.12x + 2475 - 0.15x = 2442

2475 - 0.03x = 2442

2475 - 2442 = 0.03x

33 = 0.03x

Divide both sides by 0.03

33 / 0.03 = x

3300 / 3 = x

1100 = x

Hence, the amount invested at 6% rate is $1,100.

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