In a statistics class, the female to the male ratio is 4 to 3. If there are 40 females, how many males are there? What if the ratio is 5 to 2?

Question

The professor did not explain ratios to anyone and refuses to help with this homework.

Answer 1

You can use ratios to solve in the following manner.  A ratio is simply another name for a fraction.  In this case the the number of females is in the numerator (top of the fraction) the number of males is in the denominator (bottom of fraction). By setting the two fractions equal to each other, you can solve for your missing value:

 

4/3 = 40/x

Cross-multiply (numerator of fraction 1 x denominator of fraction 2) = (denominator of fraction 1 x numerator of fraction 2)

gives you:

4x=120 - solve for x gives you x=30. So, with a 4 to 3 ratio of female to male, with 40 females, you have 30 males.

 

Similarly for a 5 to 2 ratio:

5/2 = 40/x

cross multiply

5x=80 - solve for x gives you x=16. So, with a 5 to 2 ratio, with 40 females, you have 16 males.