Answer:
Rate in still water = 45 km/h
Rate of the current = 10 km/h.
Step-by-step explanation:
Let the rate of the current be x and rate in still water be y.
So the rate of the boat upstream is y - x and the rate downstream = x + y.
Rate upstream = distance / time
y - x = 105/3 = 35 ...... (1)
Rate downstream:
y + x = 165/3 = 55 .......(2)
Adding (1) + (2):
2y = 90
y = 45 km/h.
Using equation (1):
45 - x = 35
x = 45-35 = 10 km/h.
You flip the signs when you are dividing by a negative value.
-2x+3>15
-2x>15-3
-2x>12
x<12/-2
x<-6
Now to test this
Try putting x in the original equation when it is -5.
-2(-5)+3>15
10+3>15
13>15
This is false because our answer says x is less than -6.
Now any value less than -6 will work so let's go with -7.
-2(-7)+3>15
14+3>15
17>15
This result is True.
Hope this helps out!
Answer:
7/5
Step-by-step explanation:
3x + 5 + 2x - 12 = 0
5x - 7 = 0
5x = 7
x = 7/5
Answer:
It will take 5.61 seconds for the coin to reach the stream.
Step-by-step explanation:
The height of the coin, after t seconds, is given by the following equation:
How long will it take the coin to reach the stream?
The stream is the ground level.
So the coin reaches the stream when h(t) = 0.
Multiplying by (-1)
Solving a quadratic equation:
Given a second order polynomial expressed by the following equation:
.
This polynomial has roots such that , given by the following formulas:
In this question:
So
Time is a positive measure, so we take the positive value.
It will take 5.61 seconds for the coin to reach the stream.