<span>Two trains start heading toward each other from two cities, the distance between which is 720 km, and meet right in the middle.
The second train left 1 hour after the first train, but traveled at a speed 4 km/hour faster than the first train.
Find the speed of both trains.
:
If they met half-way, each train traveled 360 mi
let s = speed of the slower train
then
(s+4) = speed of the faster train
:
Write a time equation
Slow train time - fast train time = 1 hr
- = 1
multiply equation by s(s+4), cancel the denominators</span>360(s+4) - 360s = s(s+4)<span>360s + 1440 - 360s = s^2 + 4s
A quadratic equation
0 = s^2 + 4s - 1440
Use the quadratic formula; a=1; b=4; c=-1440. but this will factor to:
(s-36)(s+40) = 0
positive solution
s = 36 mph, speed of the slow train
then obviously;
40 mph, the speed of the faster
:
:
Check this by finding the actual time of each
360/36 = 10 hrs
360/40 = 9 hrs, 1 hr less</span>
Answer:
x=3
Step-by-step explanation:
1) 10x+1-1 = 12x-5-1, this becomes a new equation
Equation: 10x = 12x-6
2) 10x-12x = 12x-12x-6, this become a new equation
Equation: -2x = -6
3) Divide both sides by -2: -2x/2 = -6/2
4) Once you simplify, you will get x=3
Hope this helps!
Answer:
7
Step-by-step explanation:
Answer:
Step-by-step explanation:
5x+2x+7=7x+7
Answer: 37.5 miles
explanation: multiply the rate of speed by the amount of time in order to find the distance:
15 miles per hour x 2.5 hours
= 37.5 miles
