90 feet of wire because 3 squared is 9 and 4 squared is 16 so 16+9=25 and the square root of 25 is 5 and 5*3=15 so that is 15 feet for one tree so 15*6=90
The answer is 3 miles per hour
Let's assume x be the number.
Given that, one number is twice the other number. Hence, the second number be 2x.
So, x= smaller number and 2x= larger number.
Given that, difference of x and half of 2x is 20. Hence,

x-x=20 (By simplifying)
0=20
From the above result we can see that x has vanish and we are left with 0=20 which is mathematically not correct.
Hence, there is no solution.
The correct answer is C because the problem showed ( x + 20 ) and ( x + 8 ) two times in the problem. That explains why there is a two outside of the parentheses.
Hope I helped! :)