Answer:
60/15 = 4 hrs
Step-by-step explanation:
1. A motorcycle driver travels 15kph faster than a bicycle rider.
The motorcycle driver covers 60 km in two hours less than the time it takes the bicycle rider to travel the same distance?:
Let s = the bike speed
then
(s+15) = the motorcycle speed
Write a time equation; time = dist/speed
Bike time - M'cycle time = 2hr
60%2Fs - 60%2F%28%28s%2B15%29%29 = 2; Sorry for the mistake here!
multiply eq by s(s+15) cancel the denominators and you have
60(s+15) - 60s = 2s(s+15)
60s + 900 - 60s = 2s^2 30s
Combiner as a quadratic equation on the left
0 = 2s^2 + 30s - 900
simplify divide by 2
s^2 + 15s - 450 = 0
Factors to
(s+30)(s-15) = 0
the positive solution
s = 15 km/hr is the bike speed
then
30 km/hr is M'cycle speed
No. It's ANY equation that when you put it on a graph, the graph is a straight line.
That almost always means
Y = Ax + B or Ax + By = C
with A, B, and C, being <u><em>any </em></u>numbers.
Another thing it means is that the x and the y are never squared or any other power ... only the 1st power ... and they're never in a denominator of a fraction.
This is the equation which you can add:
![[c + (3(c + 2))] + [5c]](https://tex.z-dn.net/?f=%5Bc%20%2B%20%283%28c%20%2B%202%29%29%5D%20%2B%20%5B5c%5D)
Simplify:
![[c + 3c + 6] + [5c] = 9c + 6](https://tex.z-dn.net/?f=%5Bc%20%2B%203c%20%2B%206%5D%20%2B%20%5B5c%5D%20%3D%209c%20%2B%206)
And, that's your answer!
Because there is an absolute value in this equation around the x and and you are only adding something to that, we know that this will always be positive. This eliminates all the choices except for [1,infinity), the third option.
