Answer:
a) $ 5000, $ 10000 b) $ 5000
Explanation:
The royalties money = $18750
She set aside 20% for new home which = 0.2 × 18750 = $ 3750
Amount remaining = 18750 - 3750 = $15000
She invested a sum in a bank certificate of deposit
let the amount invested in bank certificate = y
profit from the investment in the bank = 0.04y
second investment amount = 15000 - y
profit of investment = 0.07 ( 15000 - y)
sum of the two profit = 0.04y + 0.07 (15000 - y) = total profit = $ 900
0.04y + 0.07 (15000 - y) = 900
open the bracket and rearrange the equation
0.04y + 1050 - 0.07y = 900
0.04y - 0.07y = 900 - 1050
-0.03y = -150
divide both side by -0.03
y = -150 / -0.03 = $ 5000
The amount of money invest at 4% is $5000
The amount of money invested at 7% = 15000 - 5000 = $10000
The amount of money invested in CD account = $ 5000
