2. Roughly, it takes light less than 0.000000003 of a second to travel a one-meter distance. Express this number in the form of a × 10^n where 1 < a < 10 and is a one-digit number.

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1 point
3 x 10^8
3 x 10 ^-8
3 x 10^-9
3 x 1-0^9