Answer:
Speed of boat in still water is 6km/h
Speed of current is 4km/h
Step-by-step explanation:
We know speed = distance / time
Let the speed of boat in still water be x
Let the speed of current be y
Hence the speed of boat, down stream = 
Distance downstream = 20km
Time taken = 2 hours
We have
......(1)
Speed of boat upstream = 
Distance upstream = 4
Time taken = 2
We have
...(2)
Adding (1) & (2)
Substituting in (1) we get
X = 2 because 2+1=3 and if you want 5 then 5 - 3 = 2 so x=2
The answer to the equation is 18 which is a composite whole number. the answer is C
Answer:
let this happens after t hours
so
80t + 60t = 392
140 t = 392
t = 392/140
=2.8 hours
For a quadratic of the form
, we have the quadratic formula
,
where a is the coefficient (number before the variable) of the squared term, b is the coefficient of the linear term, and c is the constant term.
So, given
, we can get that
, and
. We substitute these numbers into the quadratic formula above.
This is our final answer.
If you've never seen the quadratic formula, you can derive it by completing the square for the general form of a quadratic. Note that the
symbol (read: plus or minus) represents the two possible distinct solutions, except for zero under the radical, which gives only one solution.
