Answer:
amount is 1000 ×
$40762.20 balance of Donna's account will be 1 million dollars when she retires in 40 years
rate 14.97 % when Donna's account will have a balance of 1 million dollars in 40 years when principal is $2500
Step-by-step explanation:
principal = $1000
rate = 8 % = 0.08
to find out
the future value, S(t)
principal when Donna's account will be 1 million dollars when she retires in 40 year
at what rate Donna's account will have a balance of 1 million dollars in 40 years
solution
we know compounded continuously formula i.e.
amount = principal × ..................1
put the value principal and rate in equation 1 to find amount any time
amount = principal ×
amount = 1000 ×
in 2nd part we have time 40 year and amount 1 million so put rate amount and time in equation 1 to find principal
rt = 0.08 × 40 = 3.2
amount = principal ×
1000000 = principal ×
principal = 1000000 /
principal = 1000000 / 24.5325302
principal = 40762.20397
so $40762.20 balance of Donna's account will be 1 million dollars when she retires in 40 years
in 3rd part we have amount 1 million and principal $2500 and time 40 year put all these in equation 1 to find rate
amount = principal ×
1000000 = 2500 ×
take ln both side
ln = ln (1000000 / 2500 )
40 r = ln 400
r = ln (400) / 40
r = 0.149787
so rate 14.97 % when Donna's account will have a balance of 1 million dollars in 40 years when principal is $2500