Question

light travels 9.45 · 10^15 meters in a year. there are about 3.15 · 10^7 seconds in a year. how far does light travel per second? write your answer in scientific notation.

Explanation:

Step1: Recall speed formula

Speed = Distance / Time. Here, distance $d = 9.45\times10^{15}$ meters and time $t=3.15\times 10^{7}$ seconds.

Step2: Perform division

$\frac{9.45\times10^{15}}{3.15\times 10^{7}}=\frac{9.45}{3.15}\times\frac{10^{15}}{10^{7}}$.
First, $\frac{9.45}{3.15}=3$.
Second, using the rule $\frac{a^{m}}{a^{n}}=a^{m - n}$, $\frac{10^{15}}{10^{7}}=10^{15 - 7}=10^{8}$.
So the result is $3\times10^{8}$.

Answer:

$3\times10^{8}$