Question

If a =2 and d=4. then s40 =​

Answer 1

Answer:

3200

Step-by-step explanation:

a = 2 | d = 4 | s40 = ?

Using formula, i.e., Sn = n/2 [2a + (n – 1) d]

S40 = 40/2 [2 x 2 + (40 - 1) 4]

S40 = 20 [4 + 39 × 4]

S40 = 20 (4 + 156)

S40 = 20 × 160

S40 = 3200

Answer 2

Answer:

$S_{40} =3200$

Step-by-step explanation:

Formula for the sum of first 'n' terms in AP is given by:

$S_{n}=\frac{n}{2} [2a+(n-1)d]$

Given:

a=2; d=4

To solve: $S_{40}$

$S_{40} =\frac{40}{2} [2(2)+(40-1)4]$

$S_{40} =20[4+156]$

$S_{40} =3200$