It would take you 35 minutes.
Since it takes 10 minutes to peel 4 potatoes, you can assume it would take 30 minutes to peel 12 potatoes (mulitiplying both numbers by 3). Then you'd add 5, instead of 10 because you are peeling 2 more potatoes than 12, instead of peeling 4, you'd divide 10 by 2 to get half the time it would take to peel half as many potatoes. Finally, add 30 and 5 to get you final answer of 35.
I hope this helps!
