Suppose that in a normal half hour of practice, a tennis player expends 280 calories of energy. How many calories who she need to expend if she were to "give 110%" effort?

308 Calories

Step-by-step explanation:

So we start off with 280 as usual, but I will focus on the percent. The given percent is 110% "effort". What we would need to do here is, Firstly, change the percent into a decimal, and this is done by moving the decimal spot of 110%. What I mean is that 110.% and you move that little period over 2 times to the left and also remove the percent as for now because we will not need it. After that you would get 1.10. This is what we will multiply by. So if we did 280x1.10 it equals 308, and that is how I got 308

Hope this helps!