At McDonald's four cheeseburgers and three medium fries have a total of 2,290 calories. Six cheeseburgers and two medium fries have 2,560 calories. How many calories does each item contain?

Question

a1234 · Answer

4c + 3f = 2290
6c + 2f = 2560

Use elimination to solve the system. Multiply the second equation by 3 and the first equation by 2.

8c + 6f = 4580
18c + 6f = 7680

Subtract.

-10c = -3100

c = 310

Put 310 into c of one equation:

4(310) + 3f = 2290

1240 + 3f = 2290

3f = 1050

f = 350

So, the cheeseburgers contain 310 calories and the fries contain 350 calories (pretty heavy).

anonymous · Answer

I'm not sure if this is accurate in calories, but man that's JUNK FOOD!

a1234 · Answer

You said it! I almost never eat at those places...

anonymous · Answer

same only when my mom is doing good in her diet lol

a1234 · Answer

:)

anonymous · Answer

Do you mind helping me with more like these because I overthink EVERYTHING!, and could use an experts knowledge. ;D

a1234 · Answer

Sure, go ahead.

anonymous · Answer

An auto parts store ordered a combined total of 40 cases of oil filters and air cleaners at a cost of $2,807.60. Each case of oil filters is $59.99. While each case of air cleaners cost $83.99. How many cases of oil filters and how many cases of air cleaners were ordered?

a1234 · Answer

Set up your equations:

x + y = 40
59.99x + 83.99y = 2807.6

Substitution looks easier for this one:

y = -x + 40

59.99x + 83.99(-x + 40) = 2807.6

59.99x - 83.99x + 3359.6 = 2807.6

-24x = -552

x = 23

Substitute:

23 + y = 40

y = 17

So, 23 cases of oil filters and 17 cases of air cleaners were ordered.

anonymous · Answer

Man you are a WIZ!

a1234 · Answer

These types of problems are kind of fun :).

anonymous · Answer

Glad you enjoy them cause I dont...

a1234 · Answer

Well keep in mind that they are actually very easy...you just have to make the equations and shift the numbers here and there.

a1234 · Answer

I hope you understood the steps I showed you.

anonymous · Answer

Definitely very clear!

a1234 · Answer

Good to hear! I have to go now, so good luck with any future problems!

anonymous · Answer

Thank you very much you too!

anonymous · Answer

ok thank you