Speed (S) = Distance (D) / time (t)
First stretch
45 = D / 2
D = 45*2
D = 90 mp
How is the same distance:
Second stretch
S = 90 / t
Average speed (AS):
AS = (S1+S2) / 2
60 = [45+(90/t)] / 2
120 = 45+90/t
120-45 = 90/t
75 = 90/t
t = 90/75
t = 1,2 h
________________________
And now:
S = 90 / t
S = 90 / 1,2
S = 75 mph
Yes what do you need help with
Answer:
No
Reasoning:
If something is a perfect cube, it is able to be put under a cube root (![\sqrt[3]{..}](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7B..%7D)
) and will result in an integer (a non-decimal number > 0, basically).
So let's calculate ![\sqrt[3]{48}](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7B48%7D)
, and see if the result is an integer.
= 3.634.......
As you can see, the result is not an integer, therefore 48 is not a perfect cube.
