Question 1 Report
The 4th term of an A.P is 13 while the 10th term is 31. Find the 21st term
Answer Details
a + 3d = 13 a + 9d = 31 6d = 18 = d = 3 a = 13 - 9 = 4 a + 20d = 4 + (20 x 3) = 64