Question

the first term of an arithmetic sequence is 8, the last term id 56 and the sum is 416. find the number of terms

Answer 1

Answer:

13

Step-by-step explanation:

first term (a) = 8

last term ( ) = 56

sum (S) = 416

number of terms (n) = ?

                              equation

                              S = n/2 (a+)

                             416 = n/2 (8+56)

                             416 = n/2 (64)

                              416 = 32n

                               n = 416/32 = 13