Two cities

The car goes from city A to city B at an average speed of 70 km/h, back at an average speed of 50 km/h. If it goes to B and back at an average speed of 60 km/h, the whole ride would take 8 minutes less. What is the distance between cities A and B?

Result

s =  140 km

Solution:


s = 70a
s = 50b
2*s = 60*(a+b-8/60)

70a-s = 0
50b-s = 0
3600a+3600b-120s = 480

a = 2
b = 145 = 2.8
s = 140

Calculated by our linear equations calculator.







Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!
avatar




Looking for help with calculating harmonic mean? Looking for a statistical calculator? Do you have a linear equation or system of equations and looking for its solution? Or do you have quadratic equation? Do you want to convert length units?

Next similar examples:

  1. Water current speed.
    river_4 Two cities along the river are 100 km apart. The powerboat downstream runs for 4 hours, upstream for 10 hours. Determines the river's current speed.
  2. Two cyclists 2
    cyclist_45 At the same time, two cyclists left the towns A and B at constant speeds. The first one going from town A to town B, and the second one from town B to town A. At one point of the trip they met. After they met, the first cyclist arrived at town B in 36min,.
  3. Motion problem
    dragway From Levíc to Košíc go car at speed 81 km/h. From Košíc to Levíc go another car at speed 69 km/h. How many minutes before the meeting will be cars 27 km away?
  4. Depth angle
    cliff From a cliff of 150 meters high, we can see the ship at a depth angle of 9° at sea. How far is the ship from the cliff?
  5. The cyclist
    cyclist_38 The cyclist drove from A to B, 60 km away. The first half drove at 30km/h, the second at 20km/h. How long did it take for him?
  6. Right Δ
    ruler Right triangle has length of one leg 28 cm and length of the hypotenuse 53 cm. Calculate the height of the triangle.
  7. Troops
    regiment Route is long 147 km and the first day first regiment went at an average speed 12 km/h and journey back 21 km/h. The second day went second regiment same route at an average speed 22 km/h there and back. Which regiment will take route longer?
  8. Two trains
    rjet Through the bridge, long l = 240m, the train passes through the constant speed at time t1 = 21s. A train running along the traffic lights at the edge of the bridge passes the same speed at t2 = 9s. a) What speed v did the train go? b) How long did it tak
  9. Diameter of a cylinder
    cylinder_horiz_2 The diameter of the cylinder is 42 cm. How many times does the cylinder turn on a 66m long track?
  10. Two gears
    gears-3 The two gears fit together. The larger gear has 32 teeth, the smaller has 20 teeth less. How many times does turn a smaller gear if the bigger gear turns three times?
  11. The rod
    meter_19 The rod has a length of 90cm. Half is painted blue, the third is red and the rest is yellow. How long is the yellow part of the rod?
  12. Vertices of a right triangle
    right_triangle_5 Show that the points D(2,1), E(4,0), F(5,7) are vertices of a right triangle
  13. Iron density
    pipe1_2 Calculate the weight of a 2 m long rail pipe with an internal diameter of 10 cm and a wall thickness of 3 mm. The iron density is p = 7.8 g/cm3.
  14. Feet to miles
    runners_6 A student runs 2640 feet. If the student runs an additional 7920 feet, how many total miles does the student run?
  15. Flooring a room
    tiles_10 Find the cost of flooring a room 6.5 m by 5 m with square tiles of sides 25 cm at the rate of rupees 9.40 per tile.
  16. A tile
    tiles_9 A tile setter is covering 5ft by 5ft square shower wall. Each tile covers 4 5/8in by 4 5/8in square. How many rows of tile are needed to reach 5ft? How many tiles are needed to cover 5ft by 5ft square
  17. Garden
    garden_1 Area of square garden is 6/4 of triangle garden with sides 56 m, 35 m and 35 m. How many meters of fencing need to fence a square garden?