Question

Number of ordered triplets of natural number (a, b, c) for which $abc\le 11$ is

• A. 52
• B. 53
• C. 55
• D. 56

Answer 1

The correct option is D 56

abc = 1 in 1 ways
abc = 2, 3, 5, 7, 11 in 15 ways
abc = 4, 9 in 12 ways
abc = 8 in 10 ways
abc = 6, 10 in 18 ways
So, total number of solution is 56