Question

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

• A. $52$
• B. $53$
• C. $55$
• D. $56$

Answer 1

Answer: (D)

$abc=1$ 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 $56$