Answer:
a. Take a grid that shows represents the amount of money Frank has,
Say F,
( shown below ),
b. Since, Marissa has twice as much money as Frank,
So, the amount Marissa has = 2F
If M represents the amount Marissa has,
M = 2F
c. Now, Christina has $20 more than Marissa,
Add 20 to the grid M
d. The below diagram provides enough information to determine the value of the variable m
e. The amount Christina has = M + 20 = 2F + 20
According to the question,
2F + 20 = 100
2F = 80
F = 40
Hence, the amount frank has = $ 40,
Amount Marissa has = 2(40) = $ 80,