Josh volunteered at the zoo for 14 hours in one month. This was 3 1/2 times as many hours as Gina volunteered. How many hours did Gina volunteer?

I think 4

14 divided by 3.5 = 4

This one you can't really make a formula for or anything, but it's fairly simple to figure out, with a bit of guess and check.

14 is really close to 15, but that's bigger, so let's try a smaller number that would work.

It has to be divisible by 2, because you've got a whole number that is 3 1/2 times the other number. (1/2 of a whole number means it's divisible by 2).

10 is divisible by 2,

10 : 2 = 5

But, 10 x 3 = 30 which is much bigger than 14.

So, we've got to start with a smaller number.

Let's try something really small, like 4. We could try 2, but 2 x 3 = 6, which, even with 1/2 of 2, isn't nearly close to 14.

Now, 4 x 3 = 12

That's quite close to 14.

And 1/2 of 4 is 2.

All we do now is add 12 to 2 and see if it works.

12 + 2 = 14

14 = 14

This one works.

That means that Gina volunteered for 4 hours, because 3 1/2 x 4 = 14.