You have 3 online accounts in three different banks valued at: bank "A" = $250.67, 12% interest, bank "B" $765.13, 7% interest, and bank "C" $28,500.36, 9% interest. What is the average interest gained from the three accounts in one year?

Step-by-step explanation:

we know that

The simple interest formula is equal to

where

I is the Final Interest Value

P is the Principal amount of money to be invested

r is the rate of interest  

t is Number of Time Periods

in this problem we have

Bank A

substitute in the formula above

Bank B

substitute in the formula above

Bank C

substitute in the formula above

Find the average interest gained from the three accounts in one year

ad = ae + ed = y + 7

similar triangles therefor

ac/ab = ad/ae

6/4 = (y + 7) / y

cross multiply

6y = 4(y + 7)

6y = 4y + 28

2y = 28

y = 14

step-by-step explanation: