speed of current is 1.5 mi/hr
Answer:
let the rate in still water be x and rate of the current be y.
speed down the river is:
speed=distance/time
speed=14/2=7 mi/h
speed up the river is:
speed=(14)/(3.5)=4 mi/hr
thus total speed downstream and upstream will be:
x+y=7...i
x-y=4.......ii
adding the above equations i and ii we get:
2x=11
x=5.5 mi/hr
thus
y=5-5.5=1.5 mi/r
thus the speed in still waters is 5.5 mi/hr
speed of current is 1.5 mi/hr
V=pie r square h/3
Hope you get the picture!
There are, 20475 different groups are possible if the manager wants to select one group of 4 people from his 28 assistants.
<h3>What is permutation and combination?</h3>
A permutation is the number of different ways a set can be organized; order matters in permutations, but not in combinations.
We have:
A manager wants to select one group of 4 people from his 28 assistants.
The total number of groups possible = C(28, 4)

After calculating:
= 20475
Thus, there are, 20475 different groups are possible if the manager wants to select one group of 4 people from his 28 assistants.
Learn more about permutation and combination here:
brainly.com/question/2295036
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Answer: it is C
Step-by-step explanation: