Question

which of the following measurements has two significant figures?
0.15 km
17.0 m
308 g
20.4 mg

Explanation:

• For 0.15 km: Leading zeros are not significant, so 1 and 5 are significant (2 sig figs).
• 17.0 m: The trailing zero after the decimal is significant, so 1, 7, 0 (3 sig figs).
• 308 g: Non - zero digits and the zero between them are significant, so 3, 0, 8 (3 sig figs).
• 20.4 mg: Non - zero digits and the zero between them are significant, so 2, 0, 4 (3 sig figs).

Answer:

0.15 km