Sum Arithmetic Progression

If the nth term of an AP is (2n+1) then the sum of its first three terms is

• 6n+3

• 15

• 12

• 21

The sum of first 'n' terms of an AP is (3n²+6n). The common difference of the AP is ______

• 6

• 9

• 15

• -3

The 5^th term of an AP is -3 and its common difference is -4. The sum of its first 10 terms is_________

• 50

• -50

• 30

• -30

The 13th term of an AP is 4 times its 3rd term. If its 5th term is 16 then the sum of its first ten terms is _______

• 150

• 175

• 160

• 135

• 149
• 11,200
• 5,600
• 140

Find the sum of the arithmetic series using a formula.

• 516, 240

• 516,242

• 116, 242

• 506, 242

The first and last terms of an AP are 1 and 11. If the sum of its terms is 36, then the number of terms will be _______

• 5

• 6

• 7

• 8

Formula to find sum of n terms in an AP is ________

• sn = a+ (n - 1)d

• $s_n$ = $\frac{n}{2}$ (2a +(n-1)d)

• $s_n$ = $\frac{n}{2}$ (2a +(n+1)d)

If the first term of an AP is –5 and the common difference is 2, then the sum of the first 6 terms is

• 0

• 5

• 6

• 15

The famous mathematician associated with finding the sum of the first 100 natural numbers is 

•  Euclid

• Newton

• Pythagoras 

•  Gauss