Question

find the sum of first 12 multiples of 7. pls answer fast tomorrow exam......!!!!!!!!!

Answer 1

First twelve multiples of 7 can be written in the form of an A.P .--> 7, 14, 21,...................... 84 , Now, Here, a =7 , d = 7 & an = 84........... Sn = n/2 [ a + l ] ............ Sn = 6 [ 7+84 ] ................. Sn = 6*91 .................. Sn = 546.

Answer 2

the sum of first 12 multiples of 7 is 546.