Nimit saves Rs. 50 during a month, Rs. 100 during next month, Rs. 150 in next month, if he continues his savings in this way, in how many months will he save Rs. 10500.
Sequence of savings is 50, 100, 150,.........
Since, common difference between any two consecutive terms is constant (i.e., 50).
So, given sequence are in A .P.
Here, a = 50, d = 50, Sn = 10,500
Since, n = –21 is not possible.
Hence an = 20
i.e., In 20 months he will save Rs. 10500.