Mathematics Problem

Question

Kelsey invests $2400 in one account and $2000 in an account paying 1 % higher interest. At the end of one year she had earned $328 in interest. At what rates did she invest?

Answer 1

2000X + 2400(X-.01) = 328

X= 8% with $2000 invested

X-.01 = 7% with $2400 invested

.08(2000) + .07(2400) = $160+$168 = $328

328/4400 = about 7.45% average interest

had equal amounts been invested, it would have been 7.5% for each

but more is invested at 7% so the average rate is slightly closer to 7 than to 8%

Answer 2

2400r + 2000(r + 0.01) = 328

Can you solve for r and answer?