Answer:
8 slices
Step-by-step explanation:
Let the watermelon eaten by Charles be A and Lisa be B
They ate 12 slices of watermelon between them
That’s
A + B = 12
Also, Lisa ate 2 times as Charles
that’s
B = 2A
We no have two equations
1. A + B = 12
2. B = 2A
Substitute 2A for B into the first equation
A + B = 12
A + 2A = 12
3A = 12
Divide both sides by 3
3A/3 = 12/3
A = 4
Charles ate 4
Recall Lisa B ate twice as Charles A
B = 2A
B = 2 x 4
B = 8
Lisa ate 8 slices of watermelon
