Answer:
- Phillip: 2 shells
- Tina: 7 shells
- Alexis: 14 shells
Explanation:
The problem statement gives rise to three equations in three unknowns. Let a, t, p represent the numbers of shells found by Alexis, Tina, and Phillip, respectively. Then the equations are ...
... a = 2t . . . . . . . Alexis found 2 times as many as Tina
... t = 5 +p . . . . . Tina found 5 more than Phillip
... a + p = 16 . . . . Alexis and Phillip together found 16 shells
These equations can be solved a variety of ways. For example, we can use substitution to get two equations in t and p.
... t - p = 5 . . . . . rearrange the second equation
... 2t +p = 16 . . . substitute for a in the third equation
Adding these gives ...
... 3t = 21
... t = 7
Then
... a = 2t = 2·7 = 14
... p = 16 - a = 16 - 14 = 2
Alexis found 14 shells, Tina found 7 shells, Phillip found 2 shells.