Question

The ratio of the 11th term to the 18th term of an ap is 2 is to 3 find the ratio of the 5th term to the 21st term and also the ratio of the sum of the first 5 terms to the sum of the first 21 terms

Answer 1

Ratio of 5th to 21st term. Of AP =1:3

Ratio of sum of first 5 term to sum of first 21 term =5:49