Question

for breakfast, randy had two egg mcmuffins and a hash brown, totaling 750 calories. Jack only had one egg mcmuffin and a hash brown, totaling 450 calories. how many calories are in each item?

Answer 1

X = egg mcmuffin
y = hash brown

Randy:     2x + y = 750 <=> 2x + 450 - x = 750 <=> x = 300 
Jack:         x + y = 450 <=> y = 450 - x <=> y = 450 - 300 <=> y = 150

1 egg mcmuffin has 300 calories
1 hash brown has 150 calories

Answer 2

Use algebra/simultaneous equations for the easy way. Let's call Egg McMuffins 'e' and Hash Browns 'h'.
So 2e + h = 750
And e + h = 450
Subtract the bottom equation from the top one
e = 300
Substitute e back in to the bottom equation (Because it's simpler)
300 + h = 450
Simplify the equation, subtract 300 from each side
h = 150

So there you go. Egg McMuffins have 300 calories and Hash Browns have 150 calories