Question

yesmeen saves RS 32 during the first month RS 36 in the second month and RS 40 in the third month .if she continues to save in this manner ,in how many month she will save RS 2000, which she has intended to give for the college fee of her maids daughter . what value is reflected here.

Answer 1

In the first month he saved Rs 32
On the 2nd month he saved Rs 36
On the 3rd month he saved Rs 40
Taking all as an AP. where a= 32
And d= 4
Also given last term is 2000
i.e l an= 2000
Now,
an = a+(n-1)d
2000 = 32 + 4n - 4
1968 = 4n - 4
1972 = 4n
n = 1972/4 = 493
Therefore after 493 months she will able to pay the fee.
This shows her love for her maid and her daughter

Answer 2

given ,
a.p.=32,36,40....
first term(a)=32 , d=4
we have given sum of n terms=2000
we have to find n,,
now,
Sn =n/2(2a+(n-1)d)
2000×2=n(2×32+(n-1)4)
4000=n(64+4n-4)
4000=n(4n+60)
4000=4n^2+60n
4n^2+60n-4000=0
4(n^2+15n-1000)=0
n^2+40n-25n-1000=0
n(n+40)-25(n+40)=0
(n+40)(n-25)=0
n=-40,n=25
n=-40 is not possible
so n=25