Kenneth recentley started a new job. his starting gross monthly salary was 3200. Each year on the anniversary of his starting date, kenneth is promised a 7% raise.

Question

If keneth works for 5 years what was his gross annual income in his fifth year of work?

my work:
A=p(1+ i)^n

A=?
p= $3200
i: 7%
n= 5

A=p(1+ i)^n
A=3200(1+0.07)^5
a= 3200(1.07)^5
A= 4488.17 I rounded it! is this correct?

there is part b to this question!

what is the minuim number of years Kenneth will have to work to earn a gross annual income of at least $60000?

I would think I would use the same formula right?

A=p(1+ i)^n

A= $60 000
p= $3200
i: 7%
n= ?

60 000 =3200(1+0.07)^n
but I get lost here how would I get n by itself?

thanks for your help!

Part A looks correct.
For part B just keep simplifying
60,000 = 3200(1+0.07)^n so
18.75 = (1+0.07)^n
Take the ln of each side to get
ln(18.75) = n*ln(1.07) so
ln(18.75)/ln(1.07) = n

show me how you calculate this eg.

Mr.Williains bought a plot og land for $40 000. The value of theland appreciated by 7% each year. calculate the volue of the land after a period of two years.

tell me how

Answer 1

use log on both sides to solve for n brandy.

Answer 2

use your scientefic calculator to find ln 18.75 and ln 1.07.