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

1 Answer

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.