Step-by-step explanation:
The amount of pizza Tina eat
[tex] = \frac{1}{4} \\ [/tex]
The amount of pizza Sam eat
[tex] = \frac{1}{2} \\ [/tex]
The amount of pizza they eat together
[tex] = \frac{1}{2} + \frac{1}{4} \\ [/tex]
[tex] = \frac{1}{2} \times \frac{2}{2} + \frac{1}{4} \times \frac{1}{1} \\ [/tex]
[tex] = \frac{2}{4} + \frac{1}{4} \\ [/tex]
[tex] = \frac{2 + 1}{4} \\ [/tex]
[tex] = \frac{3}{4} \\ [/tex]
