Question

Mr. dhanesh saves some amount every month. in first month he saves ₹400 second month ₹500, third month ₹600 etc. in which month will he save ₹2000. find his total saving in 17 months ​

Answer 1

Answer:

the first term is 400

common difference is 100

a+(n-1)*d=2000

400+100n-100=2000

300+100n=2000

100n=2000-300

n=1700/100

therefore he will save ₹2000 in the 17th month

Sn=n/2(2a+(n-1)*d)

17/2(2*400+16*100)

17/2(800+1600)

17/2*2400

17*1200

20400

therefore he will save ₹20400 in 17 months.