Question

if if the sum of first 14 terms of an ap is 1056 and first term is 10 find 20th term​

Answer 1

Step-by-step explanation:

first term = a = 10

correction in question sum is 1050 not 1056

sum of first 14 terms = 1050

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

$1050 = \frac{14}{2} (2(10) + (14 - 1)d) \\ 1050 = 7(20 + 13d) \\ \frac{1050}{7} = 20 + 13d \\ 150 = 20 + 13d \\ 13d = 150 - 20 \\ 13d = 130 \\ d = \frac{130}{13} \\ d = 10$

20th term

a20 = a + 19d

= 10 + 19(10)

= 10 + 190

= 200

hope you get your answer