Question 980792
27 students total, 7 play only MK7 and 5 play only MK8. 
27-7-5=15 There are 15 students who play neither or both.
Let n=number who play neither, 2n=number who play both.
n+2n=15
3n=15
n=5 5 students play neither
2n=2(5)=10 10 students play both.
The students who play only MK7=7 and 10 students who play both make a total of 17 students who play Mario Kart 7. ANSWER: 17