Question

using formula find the sum of first 10 terms of the series 3+7+11+..​

Answer 1

Answer:

n=10, a=3 ,d=4

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

S(10) = 10/2[2×3 + (10-1)4]

= 5[6+36]

= 5×42

= 210

Step-by-step explanation:

the sum of first 10 terms of the given series is 210.

Answer 2

Answer:

210

Step-by-step explanation:

the series are in ap

sum of terms in ap=

$\frac{n}{2}(2a+(n-1)d)$

=10/2(2*3+(10-1)4)

=5(6+36)

=42*5

=210