If 3 boys can build 4 snowmen in 24 minutes how many will 9 boys finish building in an hour

30 snowmen

Step-by-step explanation:

This is an example of a proportion, but in this case it involves 3 variables.

All we need to do is to take one as fixed variable and relate it with the other to know whether it is directly proportional or inversely proportional.

Let x be the number of snowmen 9 boys will finish building in an hour

But we first need to change 1 hour into minutes, thus; 1 hour=60 minutes

No. of boys            No. of snowmen           Time

     3 boys                       4 snowmen           24 min

     9 boys                             x                       60 min

We are going to take the number of snowmen as the fixed variable

{That is; = }  now , lets compare the number of snowmen to time, is it a direct proportion or indirect proportion? the more the time, the more the number of snowmen that will be build, this means, it is a direct proportion, so;

=

Next is to compare the number of snowmen and the number of boys, the more the number of boys, the more the number of the snowmen that will be  build, this implies that it is a direct proportion, thus;

= ×

We can now proceed to simplify

= ×

=

Cross -multiply

72× x  =  540× 4

72 x  =  2160

Divide both-side of the equation by 72

 =  

x   = 30  snowmen

addition

step-by-step explanation: