Food-energy to Mechanical Energy

[raiderIV]

Homework Statement

The nominal food-energy value of 1.00g of butter is about 7.20 food calories.

If all this energy could be converted completely to mechanical energy, how much butter would be required to power a 65.0kg mountaineer on her journey from Lupine Meadows (elevation 2070m) to the summit of Grand Teton (4196m)?

Homework Equations

Mass*Gravity*Height

The Attempt at a Solution

What I tried was (65 * 9.81 * 2126) to find the Joules of energy required for the journey. Then converted 7.2 food calories to 30.1248J and divided to find the grams.

I came out with approx 4.5x10^4g of butter, however it is not being accepted as correct.
What am i doing wrong?

 

[Doc Al]

Note that food calories are really Kcals = 1000 calories.

 

[raiderIV]

Yep that solved it...

Thank you for the correction!