Answer:
option-B
Step-by-step explanation:
We are given function as
[tex]f(x)=1200(1.055)^x[/tex]
Average rate of change between 21 and 25 years:
we can use formula
[tex]A=\frac{f(b)-f(a)}{b-a}[/tex]
so, we have
a=21 and b=25
[tex]f(21)=1200(1.055)^{21}=3693.88[/tex]
[tex]f(25)=1200(1.055)^{25}=4576.0708[/tex]
[tex]A=\frac{f(25)-f(21)}{25-21}[/tex]
now, we can plug values
[tex]A=\frac{4576.0708-3693.88}{25-21}[/tex]
[tex]A_1=220.5477[/tex]
Average rate of change between 1 and 5 years:
we can use formula
[tex]A=\frac{f(b)-f(a)}{b-a}[/tex]
so, we have
a=1 and b=5
[tex]f(1)=1200(1.055)^{1}=1266[/tex]
[tex]f(5)=1200(1.055)^{5}=1568.352[/tex]
[tex]A=\frac{f(5)-f(1)}{5-1}[/tex]
now, we can plug values
[tex]A_2=\frac{1568.352-1266}{5-1}[/tex]
[tex]A_2=75.588[/tex]
now, we can find ratio
[tex]\frac{A_1}{A_2}=\frac{220.5477}{75.588}[/tex]
[tex]\frac{A_1}{A_2}=3[/tex]
[tex]A_1=3A_2[/tex]