Explanation:
First method :-
Using unitary method,
5/2 scoops = 10 servings
1 scoop = 10/5/2 = 4 servings
15 scoops = 15 * 4 = 60 servings
15 scoops = 60 servings of bannock
Second method :-
Using proportions,
Let x be servings of bannock for 15 scoops
Let ratios be 5/2 : 10 and 15 : x
Now,
5/2 : 10 = 15 : x
or, 5/2/10 = 15/x
or, 5/2 * 1/10 = 15/x
or, 1/4 = 15/x
or, x = 15 * 4
so, x = 60
So,
15 scoops = 60 servings of bannock