The question says: derek is peeling potatoes for his large scout troop. he needs to peel a total of 85 potatoes. if he peels two potatoes in a minute, and he has already peeled 13 potatoes, how much longer will it take for him to complete the task of peeling 85 potatoes?

Derek needs to peel 85 potatoes. He's able to peel 2 potatoes each minute. Let x be the number of minutes Derek took to peel the potatoes, using the equation:
85 = 2x.
Derek has already peeled 13 potatoes, so that's 13 less. The equation is now:
85 - 13 = 2x
72 = 2x

We need to solve for x.
Let's divide both sides by 2 to have the variable x on a side and its value on the other.
72/2 = (2x)/2
36 = x.

So it will take Derek 36 MORE minutes to finish peeling all his potatoes.

Hope this helps! :D