Question

light travels 9.45x10^15 meters a year. there are about 3.15x10^7 seconds a year. how far does light travel per second?

Answer 1

(9.45*10^15)/(3.15*10^7) = (9.45/3.15)*10^(15-7) = 3*10^8

Answer 2

ANSWER:  

The speed of light is $3 \times 10^{8}$ m/s.

SOLUTION:

Given, Light travels $9.45 \times 10^{15}$ meters a year.  

And there are about $3.15 \times 10^{7}$ seconds a year.  

We need to find how far does light travel per second.

We know that, for anything, the distance, speed and time relation is given by

Distance traveled = travelling speed x time taken ----- (1)

Here, in our problem distance traveled = $9.45 \times 10^{15}$ meters a year.  

Time taken = $3.15 \times 10^{7}$ seconds.

Now, substitute the above values in (1)

$9.45 \times 10^{15}= speed \times 3.15 \times 10^{7}$

Speed = $\frac{9.45 \times 10^{15}}{3.15 \times 10^{7}}$

Speed = $3 \times 10^{15-7}$

Speed = $3 \times 10^{8}$ m/s.

Hence, the speed of light is $3 \times 10^{8}$ m/s.