Question

There are a total of 100 balloons. If the ratio of yellow balloons to blue balloons is 8 to 12, how many of them are yellow

Answer 1

If you have 8 yellow balloons for every 12 blue balloons, then if you have 20 balloons in total, 8 out of 20 of those balloons will be yellow. Then you can set up this ratio:

$\frac{8yellow}{20total} = \frac{Xyellow}{100total}$

Then, you can use either cross multiplication or multiply the numerator and denominator by the same number to help solve for x. Personally, I prefer cross multiplication, so that's what I'll show you here:

$\frac{8yellow}{20total} = \frac{Xyellow}{100total} \\ 8yellow*100total=20total*Xyellow$

Finally, solve for x:

$8yellow*100total=20total*Xyellow \\ 8*100=20*x \\ 800=20x \\ 800/20=20x/20 \\ x=40yellow$

If you had 100 balloons, you will have 40 yellow balloons.

Hope this helps!!