Image result for factor 25 into prime numbers
25 is a composite number, and it is 5 squared. 25 = 1 x 25 or 5 x 5. Factors of 25: 1, 5, 25. Prime factorization: 25 = 5 x 5, which can also be written 25 = 5².
A) mean score = (18+25+28+15+6+18+2+4+25+15)/10
= 15.6 runs
Approximately 16 runs
b) (18+25+28+15+6+18+2+4+25+15+31)/11
= 17 runs