Question

A man's salary is 800 per month in first year. he has joined in the scale of 800-40-1600. After how many years will his savings be 64,800?

Answer 1

a. 8 yrs
b. 7 yrs
c. 6 yrs
d. none of above
e. cannot be determined

Answer 2

hmm income is given but to know the savings we should know the expenditure at least.
any information given regarding expenditure??

Answer 3

u mean tax or what?

Answer 4

well expenditure like how much he spends from his salary??

Answer 5

expediture=0 then

Answer 6

if that's mentioned then,
saving in the first year = 800 x 12 = 9600
saving in the second year = 840 x 12 = 10080
now it is in A.P with common difference 480, right?

Answer 7

yes

Answer 8

hmm so suppose the saving becomes 64,800 after n years then,
n/2(9600 + 9600 + (n-1)480) = 64,800
solve for n! that's the answer.

Answer 9

Also i would like to mention that if nothing is given about expenditure and u are assuming it to be 0 then my friend, then it would be (e) because we cannot solve unless if know the value of expenditure the man incurs over the years.

Answer 10

but when salary from 800,840,840..... reaches 1600 it stops increment

Answer 11

no it will satisfy for one value given in the options....for sure!! did you solve that?

Answer 12

it gives values well above the options

Answer 13

i got the answer when i substituted the value for n=6 @mathmath333

Answer 14

but the book tells its e

Answer 15

i said you that first........ nothing mentioned about expenditure so it has to be (e). But you said it's given expenditure=0 )

Answer 16

but i was suspitious about it .....
but thanks for ur guidance

Answer 17

yeah but a large but of information is missing :)
anyways pleasure to help!!! :) no problem. anytime )