Asked by Chrissey
The fourth term of an AP is 8 and the sum of the first ten terms is 40. Find the first term and the tenth term.
Answers
Answered by
Steve
T4 = a+3d = 8
S10 = 5(2a+9d) = 40
a = 16
d = -8/3
T1 = 16
T10 = 16 + 9(-8/3) = -8
check, sequence is
16 40/3 32/3 8 16/3 8/3 0 -8/3 -16/3 -8 ...
Sum of 1st 10 terms = 40
S10 = 5(2a+9d) = 40
a = 16
d = -8/3
T1 = 16
T10 = 16 + 9(-8/3) = -8
check, sequence is
16 40/3 32/3 8 16/3 8/3 0 -8/3 -16/3 -8 ...
Sum of 1st 10 terms = 40