NO NO NO NO NO NONOOOOLOOOOOKIOI
Multiply the investment fraction by the corresponding return, and add the products. The given fractions add to 59%, so the remainder is 41%. (The total of the fractions is 100%—all of the portfolio.)
... 0.43*9.1% + 0.16*16.7% + 0.41*11.4%
... = 3.913% + 2.672% + 4.674% = 11.259%
I=1.5m
m+1.5m=20
2.5m=20
m=8
20-8=12
Isobel worked 12 hours.
A= P(1+r)^t, where P= initial value, r= interest rate in %, and t = number of years.
However, if there isa decrease in value, the formula becomes:
A= P(1-r)^t and in our case :
A = 30,000(1- 0.24)^t OR A = 30,000(0.76)^t