The correct answer is B)

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The denominator of the exponent is the root we are taking. The numerator is the exponent of the radicand. This means 3 will be the denominator, since it is a cubed root, and 2 will be the numerator of m while 5 will be the numerator of n.
Try this option, modify design according to local requirements.
Answer:
960
Step-by-step explanation:
We need to find 1/5 of 4800, we will do:
4800/5=960
So 960 is our answer.
1km = 1000m
1hr = 3600sec
Do proportions:
1km / 1000m = 15km / x
15000m = x
1hr = 3600sec
15000/3600 = 4.2m per second
Choice 4
R/9 = -21
Multiply by 9
r = -189