Answer:
0.03A + 0.03B = 800
A + B = 20000
Explanation:
Let one part A of the total money invested with 3% interest = $A
Therefore, other part B of the money invested with 5% interest = $B
Interest = Principal amount × Rate of interest × Duration of investment
If the duration is 1 year,
Interest = Principal amount × Rate of interest
Return on part A = A × 0.03
Return on part B = B × 0.05
Total return = $800
So the equations will be,
0.03A + 0.03B = 800 -------(1)
Since, total money invested = $20000
Equation will be,
A + B = 20000 -------(2)