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Question

Last year, Raina had $10,000  to invest. She invested some of it in an account that paid 9% simple interest per year, and she invested the rest in an account that paid 8% simple interest per year. After one year, she received a total of $810  in interest. How much did she invest in each account?

first account $

Second account $

Answer 1

Let x she put on 1st account. Then she put (10000 - x) on 2nd account.

Because 0.09x + 0.08(10000 - x) = 810.

Solving this equation: 0.09x + 800 - 0.08x = 810; 0.01x = 810 - 800; 0.01x = 10; x = 10/0.01; x = 1000

Answer: Raina put $1000 on 1st account and $9000 on 2nd account