Answer:
3 significant figures
Explanation:
The rules for deciding which digits in a measurement are significant are as follows:
1) All nonzero digits are significant.
2) Sandwiched (or embedded) zeros, those between significant digits, are significant.
3) Leading zeros, which are zeros at the beginning of a decimal number less than 1, are not significant.
4) Trailing zeros, which are zeros at the end of a number, are significant only if the number has a decimal point.
By rule 4 since 60.0 has a decimal point all 3 figures are significant