e = 7 ( As the total must be equal to 25. So those who do not play a sport are 25 - 18 = 7)
d= 7 ( As the total must be equal to 25. So those who do not play a musical instrument are 25 - 18 = 7)
c= 2 ( As the total for those who do not play a sport must be equal to 7)
a= 2 ( As the total for those who play a musical instrument must be equal to 7)
b= 16 ( As the total for those who play a sport must be equal to 18).