Question

Find the sum of 14 term of an ap the an=3n+5

Answer 1

Answer:

385

Step-by-step explanation:

$s = m \div 2 \: (a + l)$

Where,

m = total no. of terms = 14

a = first term = 8 (by putting the value of n = 1)

l = last term = 47 ( by putting the value of n = 14)

Now,

1. s = 14÷ 2 ( 8 + 47 )
2. s = 7 × 55
3. s = 385