Question

Suppose that Kristin ate two hamburgers and drank three medium sodas​, for a total of 1139 calories.​ Kristin's friend Jack ate seven hamburgers and drank two two medium sodas​, for a total of 2346 calories. How many calories are in the hamburger?

How many calories are in the soda? solve the systems of equation
2h+3c=1139 and 7h+2c=2346.
H represents hamburgers and c represents sodas

Answer 1

The number of calories in `1` burger is `280`

Explanation:

We just have to solve the system of equations which is
`2h+3s=1139`
`7h+2s=2346`
where `h` and `c` are the number of calories in the hamburger and soda respectively.

Isolating `s` in the second equation, we get
`s = 1173 - 7/2 h`
and substituting its value in the first equation
`2h + 3*(1173 - 7/2 h) = 1139`
now we only have to solve this equation for `h`
`2h + 3*(1173 - 7/2 h) = 1139`
`2h + 3519 - 21/2 h = 1139`
`2h - 21/2 h = -2380`
`(4 - 21) h/2 = -2380`
`- 17h = -4760`
`h = 280`//

Hope it helps.