Question

If a person burns 2171 Cal each day, how much energy (kJ) does she burn in 2 days?

Answer 1

1 Cal = 1000 cal
1 cal = 4.184 joules
1 joule = .001 kJ

First, you need to convert the Calories into kJoules
(2,171 Cal)(1000) = 2,171,000 cal
(2,171,000 cal)(4.184) = 9,083,464 joules
9,083,464 joules(0.001) = 9,083.464 kJoules

Then, multiply the value by two to get your answer

(9,083.464 kJoules)(2) = 18,166.928 kJoules

Round to the necessary significant digits