There are 110 calories per 28.4 grams of cereal x. Find how many calories all in 34.08 grams of this cereal.

Question

 This is a question that I have on a homework assignment and I am not sure how to do it. I need help and the steps would be best as well. Thank you

Answer 1

Hi Shana,

This is a question where if you lay out all of the elements carefully at the start you'll have a distinct advantage.

If you can see it, you begin with a ratio of calories per gram of cereal (110 C/ 28.4 g). This ratio is a quality specific to the cereal itself, ie. no matter how many grams of cereal you have, the number of calories will increase proportionally and the ratio will remain the same.

Now try to set up an equation, using the fact that the ratio of Cal/gram is constant:

110 cal / 28.4 g = x cal/ 34.08 gram

Because the ratio should be the same, 110/28.4 should be equal to x (what your trying to solve) /34.08

Once the problem is set up correctly, it's a normal algebra problem where you multiply both sides of the equation by 34.08 in order to isolate x, your unknown variable.

This gives you:  (110cal/28.4g) * 34.08g = x cal

If you would like to note, when you keep the units and multiply the left side of the equation, the "grams" unit cancels out (grams/grams), leaving you only the number of calories, which is what you are looking for.

Hope that helped, and good luck!
Joseph

Answer 2

Hi Shana,

 

Here you want to set a proportion to solve.

 

we will make the proportion in this format.

 

110 calories           x calories

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

28.4 grams           34.08 grams

 

 

Now you have a proportion to solve

 

110          x

-----  =  ------

28.4      34.08

 

110 (34.08)=28.4x

 

3748.8 = 28.4x

 

x= 132

 

So the answer is 132 calories in the 34.08 gram cereal.