I did the math in my head and it equals 240
Recall your d = rt, distance = rate * time.
going forth and back is 80 miles, thus upstream as well as downstream is just 80 miles.
now, bear in mind that say, the boat has a "still water" of "b", when going downstream, is not going "b" fast is going "b+7" because the current's is adding to it, likewise when is going upstream is going "b-7" because is going against the current and thus the current is eroding speed from it.
now, the whole trip took 3 hours and 20 minutes, bearing in mind that 20 minutes is 1/3 of an hour, so is 3 and 1/3 hours, or 10/3 of hours.
if say it took "t" hours going down, then going up it took the slack from 10/3 and "t", that is, it took "10/3 - t".
The question is asking you to organize the data in line plot form. to do so you must create a number line (which in this case is provided for you) and put X's above the numbers. for example lets say your given the following data :
1, 2 ,2 , 4 , 1 , 3 , 2 , 5
this is how you would graph it in line plot form
x . x
x . x . x . x . x
_________________________________________
1 . . . 2 . 3 . 4 . 5
but in your case not al the numbers listed are on the plot so instead you do this:
x . x
x . x . x . x . x
___________________________________
1 . 3 . 5 .
plot as if the numbers are there. ( as usual spacing is important)
Option C
2100 different committees that can be formed from 5 teachers and 10 students
<em><u>Solution:</u></em>
A school committee consists of 2 teachers and 4 students
The number of different committees that can be formed from 5 teachers and 10 students is to be found
This is a combination problem
A combination is a selection of all or part of a set of objects, without regard to the order in which objects are selected
<em><u>The formula to calculate combinations is:</u></em>
where n represents the number of items, and r represents the number of items being chosen at a time
Here we have to choose 2 teacher from 5 teacher and 4 student from 10 student
Hence we get,
Number of committees =
To get the factorial of a number n the given formula is used,
Therefore,
Thus 2100 different committees that can be formed from 5 teachers and 10 students