Answer
She will not burn of the calories she is claiming to burn off. It would take her $ 4.36 \times 10^3$ reps to burn off the chocolate bar.
Work Step by Step
We calculate how many reps she will need. We use unit conversions to find that the energy is equal to: $=230\times4184=9.6\times10^5 \ J$. Now, we see how many reps, which we will call x, are needed:
$9.6\times10^5 \ J=(45)(.5)(x)g \\ x = 4.36 \times 10^3$
This is much more than 5, so she will not burn of the calories she is claiming to burn off.
