Assum,e that she put x in the account of 3%
So in wizard bonds, she put twice so it is 2x
The rest in the account of 4%
The rest is 100,000 - x - 2x = 100,000 - 3x
The rule of the investment is :
I is the interest, P is the money she invested, r is the rate and t is the time
We will make equation for each account
The sum of the interest is 4,480, so add them and equate the sum by 4,480 to find the value of x
0.03x + 0.11x + 4000 - 0.12x = 4,480
Add like terms in the left side
0.02x + 4000 = 4,480
Subtract 4000 from both sides
0.02x + 4000 - 4000 = 4,480 - 4000
0.02x = 480
Divide both sides by 0.02
x = 24,000
The value in the mutual fund is 100,000 - 3x, so substitute s by 24,000
The mutual fund = 100,000 - 3(24,000) = 100,000 - 72,000 = 28,000
The mutual fund = $28,000