How many terms of the series
`1 + 3 + 3 ^(2) + …` must be taken to meke 3280?

How many terms of the series 54 + 51 + 48 + … must be taken to make 513 ? Explain ? Explain the -double anwer.

How many terms of the series 1+2+2^2+….. must be taken to make 511?

How many terms of the series 2+6+18+ . . . . . . . . . . . Must be taken to make the sum equal to 728 ?

How many terms of the series 1+3+3^2+3^3+3+....+3^(n-1) must be taken to make the sum equal to 3280.

How many terms of the series 2 +6+ 18+ ... must be taken to make the sum equal to 728?

How many terms of the sequence sqrt(3),3,3sqrt(3) must be taken to make the sum 39+13sqrt(3)?

How many terms of the AP: 9, 17, 25, . . . must be taken to give a sum of 636?

Find how many terms of the series 17+ 15+13 +…… must be added to get sum equal to 72 ?

How many terms of the A.P. 20, 19 1/3, 18 2/3, ……… must be taken so that their sum is 300?

How many terms of the series 1+2+4+…. Has the sum 511 ?