Find the Sum of `5+8+11+....`to 10 terms using formula.

Find the sum of the series 3+7+11+…..to 10 terms.

Find the sum of i] 41, 36, 31, ....... upto 10 terms ii] -26, -24, -22, ..... upto 36 terms.

Find the sum of the series 3+7+11+….. to 10 terms.

Find the sum: 5/4+ ((-11)/4)

Find the sum of series to n terms 5,5,5,5,"…." .

Find the 60th term of an A.P 8, 10 , 12, .....if it has a total of 60 terms and hence find the sum of its last 10 terms. OR Find the sum of all natural numbers between 200 and 300 which are exactly divisible by 6.

The sum of the first 8 terms of an A.P. is 100 and the sum of its first 19 terms is 551. Find the first term and the common difference of the AP.

Find the sum of all even natural numbers from 2 to 40 by using the formula.

Find the sum of indicated number of terms in each of the following Aps (i) 16, 11,6,….., 23 terms (ii) -0.5, -1.0, -1.5 ,………,10 terms (iii) -1,1/4,3/2 ,…..10 terms