If you only go by 60.0 g, the answer will need 3 sig figs.
When you're dealing with a decimal number, try to remember that
- Non-zero digits and zeros that come after them before the decimal are significant;
In your case, you have 6 and 0 before the decimal, so that's two sig figs right off the bat. By comparison, 060.0 would still have 2 sig figs before the decimal, because the first zero does not count.
- If you have non-zero digits before the decimal, all digits after the decimal are significant;
You only have 1 digit after the decimal, a zero, but because you had a 6 before the decimal, it counts as a sig fig as well.
- If you only have zeros before the decimal, only non-zero digits and zeros that come after them are considered significant after the decimal.
For example, 0.02 only has 1 sig fig, because you only have zeros before the decimal, so only the 2 after the decimal counts.
At the same time, 0.020 has 2 sig figs, because you have a non-zero digit followed by a zero digit in the decimal portion.
As a conclusion, your answer must have 3 sig figs because 60.0 has 3 sig figs.