Chad takes in 21 calories per snack. In all, how many snacks does Chad have to eat to consume a total of 42 calories?

Chad has to eat 2 snacks because 21+21=42

Let y be amount of calories

let x be amount of snacks

the equation is y=21x

you know there's 42 calories so substitute that in: 42=21x

divide each side by 21: 2=x

The answer is: Chad needs to eat 2 snacks to consume 42 calories