Question

Ben started a job that paid $40,000 a year. Each year after the first, his salary was increased by 4%.
a. what was Ben's salary in his eight year of employment?
b. What is the total amount that Ben earned in eight years?

Answer 1

First find the salary for each year starting with

1st = 40,0000
2nd =
3rd =
.
.
.
8th =

Then use geometric series formula

Answer 2

ok, give me a sec

Answer 3

its not arithmetic

Answer 4

oh you changed it, never mind

Answer 5

do you know what 1.04^7 is, i dont have a calculator...

Answer 6

Am i doing it right?

Answer 7

does anyone know what 1.04^7 is?

Answer 8

is the answer 5236.2711696?

Answer 9

DUDEEEEE ANSWER MEEEEEE

Answer 10

@ghazi

Answer 11

Anyone?

Answer 12

@LonelyandForgotten

Answer 13

have you solved it?

Answer 14

yes

Answer 15

my answer is above

Answer 16

8 years ago , his salary was 28800

Answer 17

annual

Answer 18

ago?

Answer 19

how did u get that

Answer 20

this is what your question says :) 8 years ago

Answer 21

where does it say that?

Answer 22

i guess i misread or misunderstood the question, the first part

Answer 23

its alright, please try to find the answer and get back to me

Answer 24

sure :)

Answer 25

No @ghazi, you mis-interpreted the question. It says nothing about "eight years ago".

Answer 26

@hero yeah that's what i said :(

Answer 27

does anyone understand it yet? Still need to understand it if you guys can get back to me

Answer 28

i gave an answer above, was it right?

Answer 29

is it correct that i do 1.04^7?

Answer 30

because thats the common ratio

Answer 31

and n becomes 7

Answer 32

@hartnn

Answer 33

its neither arithmetic, nor geometric, its something else only.....
1st term a1= 40000
2nd term a2= 40000+0.04*40000 = 1.04a1
3rd term a3 = a2+0.04a2 = 1.04 a2
and so on.
an = 1.04*a(n-1)
with a1=40000

Answer 34

@hartnn, I hate to disagree with you, but it is geometric

Answer 35

oh...but how ?

Answer 36

I'm not going to try to explain. Look up the general formula for sum of geometric series

Answer 37

its because theres a common ratio, im pretty sure

Answer 38

1) Each year after the first, his salary was increased by 4% 'of first yr salary' <-----------yes , its arithmetic series with common diff. 0.04*40000
2) Each year after the first, his salary was increased by 4%. 'of previous yr' <-----------neither geometric nor arithmetic...and general term is as i shown above.

Answer 39

an = 1.04*a(n-1)
an = 1.04^(n-1)*a1
so after 8 years
a8 = 1.04^7 a1 = 1.04^7 * 40000= .....

Answer 40

^ that was for 2nd case.
for 1st case , u directly have formulas for arithmetic series.

Answer 41

the second part of the question asks for the total amount earned over the 8 years which means you use the sum formula, s_n/2(a1+an)? Correct me if im wrong

Answer 42

i would like to correct myself :
1) Each year after the first, his salary was increased by 4% 'of first yr salary' <-----------yes , its arithmetic series with common diff. 0.04*40000
2) Each year after the first, his salary was increased by 4%. 'of previous yr' <------------geometric ...and general term is as i shown above.
to answer that Q of yours, what should i assume ? 1st case or 2nd case ?

Answer 43

i think 2nd case, as correctly pointed by Hero, that its geometric.
and you have standard formula for sum of Geometric series.

Answer 44

I just wanna know if my answer for the first case if correct, i got 5236.2711696

Answer 45

how its less than 40 000 ??
1.04^7 * 40 000 = 52637.27
that will be his salary after 8 years.

Answer 46

for sum, use formula, a(r^n -1) / (r-1)
r= 1.04, n=8,a=40 000

Answer 47

my mistake, i got that on my calculator though typed it in wrong

Answer 48

no problem! even i did a mistake interpreting this problem at first, seems Hero was correct all along....