Posted by John on .
In an AP the first term is 2 and the nth term is 29 and the sum of the n term is 155 find n

maths 
Steve,
we know that 2+(n1)d = 29, so
d = 27/(n1)
sum of first n terms is
n/2 (4+(n1)d)
n/2 (4+(n1)*27/(n1)) = 155
n = 10
check:
d = 27/9 = 3
10th term is 2+9(3) = 29
S10 = 5(4+9(3)) = 155