Answer:
40 kph
Step-by-step explanation:
I'm not to familiar with km but if it took you 30 minutes to travel 20km you would have to be going 40kph. It's basic math too. If you went 20 kph for 20km it would take you an hour to get there, but since they made it in 30 minutes, you just double the speed.
Answer:
84
Step-by-step explanation:
We can set up a proportion using fractions.

Now, let's cross multiply by multiplying 12 and 28 then dividing by 4.

Hope this helped!
From the attached graphic:
e = c*h/wavelength therefore,
wavelength = c*h / e
wavelength = 299,792,458 * 6.62606957e-34 / 3.38x10^-19
wavelength = 5.8771e-7 meters
9/10 or 0.9
Hope this helps
Answer:
You need to add a picture so we can help