Deposit

We deposited a total of $15,000 into simple interest accounts. The annual simple interest rate on one account at 6% the annual simple interest rate on the second account at 7%. How much should be invested in each account so that the total interest earned is $970

Correct answer:

a =  8000
b =  7000

Step-by-step explanation:

$$\begin{gathered} p_1=6\%=\frac{6}{100}=\frac{3}{50}=0.06 \\ {p}_2=7\%=\frac{7}{100}=0.07 \\ a+b=15000 \\ {p}_1\cdot a+p_2\cdot b=970 \\ a+b=15000 \\ 0.06\cdot a+0.07\cdot b=970 \\ a+b=15000 \\ 0.06a+0.07b=970 \\ Row2-0.059999999999945\cdot Row1\to Row2 \\ a+b=15000 \\ 0.01b=70 \\ b=\frac{70}{0.01}=7000.00000001 \\ a=15000-b=15000-7000.00000001=7999.99999999=8000 \\ a=8000 \\ b=7000 \end{gathered}$$

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