Question

The sum of the 7th and the twice 11th term of an arithmetic progression equal 113. The sum of the 8th and the twice 13th term of the sa,e progression equal 113. Calculate the first term and the common difference of the progression.

Answer 1

s7+2 (s11)=113
s8+2 (s13)=113
solve these 2 equation u will get ans