a+d = 4a
a = 10
10+d = 40
d = 30
S12 = 12/2 (2*10 + 11*30)
The second term of an arithmetic progression I four times the fits term, and the first term is ten.
Find the common difference and hence find the sum of the first 12 terms.
2 answers
The sum of the 3rd and 7th term of an AP is 38 and the 9th term is 37.find the AP
2 answers