The question you asked uses the concept of division, something that a bit tricky at first but gets easier as you master it!
So first let’s write and equation for your problem:
Let x = the amount of calories she burns each hour.
So we already know that Vivi was drumming for 3 hours, that she burned 756 calories, and that she burned the same amount of calories each hour.
Since she burned 756 calories in total, we know that the equation will have to equal 756:
= 756
We also know that the answer will be 3(hours) times x(the amount of calories), so now we just plug it into the equation:
3x = 756
To find what ‘x’ equals we have to divide both side by 3:
3x/3 = 756/3
Now all we have to do is simplify and you have your answer!
x = 252
And there you have it, Vivi burned 25 calories per hour!
Hope this helps! :)