Write the Number in Scientific Notation $2 \times 10 ^ { 9 }$

Multiple Choice

Write the number in scientific notation.
-The hard drive of the computer has a capacity of 20 gigabytes. (The prefix giga means 1 billion) .

A) $2 \times 10 ^ { 9 }$ bytes
B) $2 \times 10 ^ { 13 }$ bytes
C) $20 \times 10 ^ { 9 }$ bytes
D) $2 \times 10 ^ { 10 }$ bytes