Select all pairs of numbers that have a least common multiple of 18. a. 2 and 6 b. 3 and 6 c. 2 and 9 d. 6 and 9

IN this question we have to find all the pairs out of the four given options , whose least common multiple is 18 .

The first pair is 2 and 6, and for this pair, the common multiple is 6.

For the second pair 3 and 6, whose common multiple is 6 .

For the third pair 2 and 9, the common multiple is the product of them , that is  2 times 9 which is 18.

For the last pair, which is 6 and 9, the least common multiple is 18 .

So the correct options are C and D .