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How many 2-digit numbers are multiples of 2 but not 3?

1 Answer

3 votes

Answer:

30 numbers

Explanation:

Two-digit numbers divisible by 2 are basically just the even two-digit numbers: 10, 12, 14,...96, 98.

Let's collectively divide all these numbers by 2:

10/2 , 12/2 , 14/2 , ... 96/2 , 98/2

5, 6, 7, ... 48, 49

Now subtract 4 from each of them:

5 - 4, 6 - 4, 7 - 4, ... , 48 - 4, 49 - 4

1, 2, 3, ... , 44, 45

So there are 45 multiples of 2 that are two-digit numbers.

The numbers that are both multiples of 2 and 3 are those that are multiples of 6:

12, 18, 24, ... , 96

We want to count how many there are, so divide all these numbers by 6:

12/6 , 18/6 , 24/6 , .... , 96/6

2, 3, 4, .... , 16

There are 15 numbers that are multiples of 2 and 3, so subtract 15 from 45: 45 - 15 = 30

The answer is 30.

Hope this helps!

User Andrea Angeli
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