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

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

Solution:

Required number of ways of getting different products $={ }^{4} C_{2}+{ }^{4} C_{3}+{ }^{4} C_{4}=6+4+1=11$