Question

In a new year ,Reenu saved Rs.50 in the 1 st week and Then increased her weekly saving byRs. 17.50 .If in the nth week ,her weekly saving becomes ₹207.50 ,find the value of n.

Answer 1

Answer:

Weekly saving by Reenu in successive weeks are Rs.50,67.50,85,102.50,.........,207.50

This is clearly an Ap with a=50,d=17.50and l=207.50

Let the number of terms af this AP be n.Then,

Tn=207.50

a+(n-1)d =207.50

50+(n-1) ×17.50 =207.50

(n-1) ×17.50=207.50-50=157.50

(n-1)=157.50/17.50=9

So n=10

Hence , Reenu 's weekly saving wiil be Rs.207.50 in 10 th week.

Answer 2

Answer:

Weekly saving by Reenu in successive weeks are Rs.50,67.50,85,102.50,.........,207.50

This is clearly an Ap with a=50,d=17.50and l=207.50

Let the number of terms af this AP be n.Then,

Tn=207.50

a+(n-1)d =207.50

50+(n-1) ×17.50 =207.50

(n-1) ×17.50=207.50-50=157.50

(n-1)=157.50/17.50=9

So n=10

Hence , Reenu 's weekly saving wiil be Rs.207.50 in 10 th week.