Question

At an interest rate of 4% compounded annually, how long will it take to double the following investments? (Round your answer to the nearest year.)
(a) $100
_____ years

Answer 1

why is it not 25?

Answer 2

200 = 100(1 + 0.4)^n

solve for n

Answer 3

wait isnt n 1

Answer 4

(1.04)^n = 2
n ln 1.04 = ln 2
n = ln 2/ ln 1.04 = 17.67

18 years

Answer 5

why does 1.04^n = 2?

Answer 6

(1.04)^n = 200/100

Answer 7

i dont get what u did after that. could u retricewords to explain ur steps?

Answer 8

retrice? i said USE

Answer 9

have you seen the formula before
ie amount = principap ( 1+ annual rate) ^ number of years

A = P(1 + r)^n

Answer 10

yes i have

Answer 11

u get 2=1.04^n and then what

Answer 12

how do u get 18?

Answer 13

(1.04)^n = 2
when the unknown is the exponent you then take logarithms (logs) of both sides

do you know about logs?

Answer 14

sorry i have to go out for a while marion - maybe we can talk later

Answer 15

not really no.
and thta's fine. the name is mario by the way.

Answer 16

*that's