Two cars are 100 miles apart. If they drive towards each other they will meet in 1 hour. If they drive in the same direction they will meet in 2 hours. Find their speed by using graphical method.
Answers
Answer:
Their speed are 25 km/h and 75 km/h
Step-by-step explanation:
Define x:
Let x be the speed of Car A
Let y be the speed of Car B
If they travel in opposite direction:
Distance = Speed x Time
Car A = 1x miles
Car B = 1y miles
Total distance is 100 miles
x + y = 100
If they travel in the same direction:
Distance = Speed x Time
Car A = 2x miles
Car B = 2y miles
They meet after 2 hours
2x = 2y + 100
Solve it graphically:
Plot the two linear line
1) x + y = 100
2) 2x = 2y + 100
* See attachment for the graph
Their speed are 25 km/h and 75 km/h
Solve it using system:
Equations:
x + y = 100 ----------- [ 1 ]
2x = 2y + 100 ------- [ 2 ]
[ 1 ] x 2:
2x + 2y = 200 --------------- [ 1a ]
Sub [ 2 ] into [ 1a ]
2y + 2y + 100 = 200
4y + 100 = 200
4y = 100
y = 25
Find x from [ 1 ]:
x + y = 100
x + 25 = 100
x = 75
Find their speed:
Car A = x = 25 km/h
Car B = y = 75 km/h
Answer: Their speed are 25 km/h and 75 km/h
