2 Answers

MINNU

Let a be the first term and d be the common difference.Now, t4t7 = 23⇒a+3da+6d = 23⇒3a+9d = 2a+12d⇒a = 3dNow,t3t11 = a+2da+10d = 3d+2d3d+10d = 5d13d = 513

Sivapriyanka


FORMULA:
a+(n-1)d;
a+3d=2;a+6d=3;on solving we get,
a=1,d=1/3;

substitute it on the equation,
a+2d and a+10d
we get 5:13