Answer:
C
Step-by-step explanation:
5x 2nd power -(-4x 2nd power) makes it a positive which is 9x 2nd power then 9x 2nd power +(-3x 2nd power) which + and - make it 9x 2nd power-3x 2nd power which equals 6x 2nd power. The only answer choice with 6x 2nd power is C.
> is the answer. greater than
Answer: Train A = 50 mph; Train B = 30 mph
Step-by-step explanation:
In this case, let's call the speed of both trains as:
Va: speed of train A
Vb: speed of train B
As train A is faster than train B, let's call speed of train B as X; So if Vb is X, then Va would be:
Vb = X
Va = X + 20
If we combine both Speed, we have:
V = Va + Vb = X + X + 20 = 2X + 20
Now that we have an expression for the combined speed, let's recall the formula for speed in general:
V = d/t
Where:
d: distance = 240 miles
t: time = 3 hours
Combining all the data we have:
V = 240/3
but V is 2X + 20 so:
2X + 20 = 240/3
Solving for X:
2X + 20 = 80
2X = 80 - 20
2X = 60
X = 60/2
X = Vb = 30 mph
Now that we know speed of one train, we can know the speed of the other train:
Va = 30 + 20 = 50 mph
