Final answer:
The number 6.7 x 10³ has two significant figures, 6 and 7.
Step-by-step explanation:
The number 6.7 x 10³ has two significant figures. The non-zero digits, 6 and 7, are significant. Zeros that are located between non-zero digits are also significant. However, leading zeros, which are zeros that come before non-zero digits, are not considered significant. In this case, the leading zero in 6.7 is not significant, so we only count the digits 6 and 7, resulting in two significant figures.