Permutation and CombinationHard

Question

A man saves Rs. 200 in each of the first three months of his service. In each of the subsequent months his saving increases by Rs. 40 more than the saving of immediately previous month. His total saving from the start of service will be Rs. 11040 after

Options

A.19 months
B.20 months
C.21 months
D.18 months

Solution


1             2             3          4           5           6       .....
200       200       200       240       280       .....       .....
Sum = 11040
120 + 80 + 160 + 40 + 200 + 240 + .... = 11040
[2a + (n - 1)d] + 80 + 40 = 11040
[2a + (n - 1)40] = 10920
n [ 6 + n - 1 ] = 546
n (n + 5) = 546
n = 21

Create a free account to view solution

View Solution Free
Topic: Permutation and Combination·Practice all Permutation and Combination questions

More Permutation and Combination Questions

Number of ways of placing 5 different balls in 3 different boxes (no box remains empty), is ---...The number of ways to make 5 heaps of 3-3 books each from 15 different books a-...The straight lines I1, I2, I3 are parallel and lie in the same plane. A total number of m points are taken on I1; n poin...All letters of the word ′AGAIN′ are permuted in all possible ways and the words so formed (with or without m...How many six letter words be made out of the letters of ′ASSIST′ ? In how many words the alphabet S alternat...