Answer: he invested $5300 at 11% and $1000 at 6%
Step-by-step explanation:
Let x represent the amount which he invested in the first account paying 11% interest.
Let y represent the amount which he invested in the second account paying 6% interest.
He Invest $6,300 in two different accounts the first account paid 11% the second account paid 6% in interest. This means that
x + y = 6300
The formula for determining simple interest is expressed as
I = PRT/100
Considering the first account paying 11% interest,
P = $x
T = 1 year
R = 11℅
I = (x × 11 × 1)/100 = 0.11x
Considering the second account paying 6% interest,
P = $y
T = 1 year
R = 6℅
I = (y × 6 × 1)/100 = 0.06y
At the end of the year, he had earned $643 in interest , it means that
0.11x + 0.06y = 643 - - - - - - - - - -1
Substituting x = 6300 - y into equation 1, it becomes
0.11(6300 - y) + 0.06y = 643
693 - 0.11y + 0.06y = 643
- 0.11y + 0.06y = 643 - 693
- 0.05y = - 50
y = - 50/ - 0.05
y = 1000
x = 6300 - y = 6300 - 1000
x = 5300
= 0.2