Question

find sum of
15 + 11 +7+ ... + (-13)

....

plz help me....​



this is a question of chapter ap....​

Answer 1

Answer:

15+11+7=39 achcha question hai aur iska answer first wali digit se nain ko dheere dheere karke -13 ke piche le jao aur jo answer bachega vah tumhara answer hoga

Answer 2

Answer:

a=15

d=11-15=-4

an=-13

$an = a + (n - 1)d \\ - 13 = 15 + (n - 1) - 4 \\ - 13 = 15 - 4n + 4 \\ 4n = 15 + 4 + 13 \\ 4n = 32 \\ n = 8 \\ s8 = \frac{8}{2} (a + an) \\ = 4(15 - 13) \\ = 4 \times 2 \\ = 8$

sum of ap is 8