How fast should your spacecraft travel so that clocks on board will advance 10.7 times slower than clocks on Earth?

The value is  

Explanation:

From the question we are that

  The number by which the clock on the spacecraft should be slower than that on the earth is  

 Generally from the time dilation relation given by Albert Einstein we have that

Here is the time on earth

        is the time on the spacecraft

        v is the speed of the spacecraft

        c is the speed of light with value  

So

Given that

So

i'm just gonna leave this comment here, so i can get a challange done-

explanation: