Answer:
13 players
Explanation:
Let
n = number of players on the team
c = number of players who eat chocolate
s = number of players who eat strawberry
p = number of players who eat pineapple
a = number of players who eat all toppings
13 players eat chocolate topping
c = 13
10 eat strawberry
s = 10
12 eat pineapple
p = 12
So far,
n = c + s + p = 35
4 eat both chocolate and strawberry
n = 35 -4 = 31
5 eat both strawberry and pineapple
n = 31 - 5 = 26
7 eat both chocolate and pineapple
n = 26 - 7 = 19
3 eat all three toppings
n = 19 - 3 -3 = 13