unit rates

Question

for a class trip 114 students are put on 4 buses. at this rate how many students would be on 8 buses

Answer 1

Hi Maria (fellow Westchester citizen!)

 

Truthfully, you don't really need the "unit rate" here, you just double the number you have, since 8 buses is twice as many as 4 buses. So you'd have 114 x 2, which is 228 students.

 

BUT, if you want to do it with "unit rates..."

 

The key is to figure out how many students would fit on ONE bus--that's the "unit" part.

 

You know that 114 go on 4 buses, so divide by 4 to see how many go on 1 bus:

 

114 ÷ 4 = 28.5 (we know we can't have ".5 of a kid," but don't worry about that for now.)

 

Now that we know how many can go on one bus, you just multiply that number by 8 to see how many go on 8 buses.

 

28.5 x 8 = 228 students on 8 buses.

 

Hope this helps!

 

Matt, up the road in Ossining. :-)

Answer 2

The unit rate = 114 students/4 buses = 28.5 students per bus.

 

(28.5 students per bus)*(8 buses) = 228 students

 

-----

 

You can also use a scale-up proportion:

 

    4 buses             8 buses

------------------ = ----------------

114 students       x students

 

8 buses is 2 times as many as 4 buses, so x is 2 times as many as 114 students = 228 students.  Or you can cross multiply:

 

4x = 8*114

x = 2* 114

x = 228