How many different products can be obtained by multiplying two or more of the numbers 3, 5,7, 11 (without repetition)?

Answer

11

Explanation

Required number of products
= number of ways of selecting 2 or 3 or 4 numbers out of 3, 5, 7, 11
`=(.^(4)C_(2)+.^(4)C_(3)+.^(4)C_(4))=(6+4+1)=11`.