Sam sold half as many as Odel.
That means Odel sold twice as many as Sam.
Let x = number of pizzas sold by Sam.
Then Odel sold 2x.
Altogether they sold 126
x + 2x = 126
3x = 126
x = 42
Since x is the number of pizzas sold by Sam, that is our answer.
Answer: Sam sold 42 pizzas.