Question

ramkali saved Rs5 in the first week of a year and then increased her weekly savings by Rs 1.75 if in the nth week her weekly savings become Rs 20.75 find'n'

Answer 1

Ramkali saved in 1st week = 5 ₹

and increase per week = 1.75₹

We observe here,

5 , 6.75 , 8.5 ,.........20.75 are in AP

where, a = 5 , d = 1.75 and Tn = 20.75

Tn = a + ( n -1)d

20.75 = 5 + (n -1)1.75

15.75 = 1.75(n -1)

9 = n -1

n = 10

Answer 2

Money saved in first week=₹5
A.T.Q.
5+n(1.75)=20.75
1.75n=20.75-5
1.75n=15.75
n=15.75/1.75
n=9
So,her savings will become ₹20.75 in 9th week