Diane must choose a number between 49 and 95 that is a multiple of 2, 3, and 9. Write all the numbers that she could choose. If there is more than one number, separate them with commas?

The set of numbers that Diane can choose is:

{54, 60, 66, 72, 78, 84, 90}

Finding common multiples of 2, 3, and 6:

A number is a multiple of 2 if the number is even.

A number is a multiple of 3 if the sum of its digits is multiples of 3.

A number is a multiple of 6 if it is a multiple of 2 and 3.

Then we only need to look at the first two criterias.

First, let's see all the even numbers in the range (49, 95)

These are:

{50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94}

All of these are multiples of 2.

Now we need to see which ones are multiples of 3.

To do it, we sum its digits and see if that sum is also a multiple of 3.

50: 5 + 0 = 5 this is not multiple of 3.

52: 5 + 2 = 7 this is not multiple of 3.

54: 5 + 4 = 9 this is multiple of 3, so 54 is a possible number.

And so on, we will find that the ones that are multiples of 3 are:

54: 5 + 4 = 9.

60: 6 + 0 = 6

66: 6 + 6 = 12

72: 7 + 2 = 9

78: 7 + 8 = 15

84: 8 + 4 = 12

90:9 + 0 = 9

Then the numbers that Diane could choose are:

{54, 60, 66, 72, 78, 84, 90}

If you want to learn more about multiples, you can read: