Respuesta :
Answer:
At 6% interest rate, amount invested = $7000
At 8% interest rate, amount invested = $21000
Step-by-step explanation:
Let amount invested in one account be x and amount invested in the other be y.
Thus;
x + y = 28000 - - - - (eq1)
Interest rate for them are 6% and 8% annually.
We are told that total interest earned for the year was $2100
Thus;
0.06x + 0.08y = 2100 - - - - (eq 2)
Make x the subject in equation 1.
x = 28000 - y - - - - (eq 3)
Put 28000 - y for x in eq 2
0.06(28000 - y) + 0.08y = 2100
1680 - 0.06y + 0.08y = 2100
0.02y = 2100 - 1680
0.02y = 420
y = 420/0.02
y = 21000
Put 21000 for y in eq 3 to get;
x = 28000 - 21000
x = 7000
Thus amount invested in each account is;
At 6% interest rate, amount invested = $7000
At 8% interest rate, amount invested = $21000
