Therefore, it will take them hours working together to paint the apartment.

Recall the relationship between , time and distance.

It is distance = speed ´ time.

In symbols, d = rt

Example A car traveled to go for 500 miles in 10 hours. Find it’s speed per hour?

You want to know the speed of the car.

Substituting d = 500 miles and t = 10 hours

\ 500 = r (10)

\ 50 = r

So, the speed of the car is 50 miles per hour.

Example The distance between the two cities A and B is 600 miles Alice starts from A and is traveling towards B with a uniform speed of 60 miles per hour. At the same time Dick starts from B and is traveling towards A with the uniform speed of 40 miles per hour. When and where will they meet ?

Let them meet after x hours from the start of the journey. During x hours,

Alice has covered a distance 60 ´ x = 60 x miles.

Dick has covered a distance 40 ´ x = 40 x miles.

Hence we must have 60 x + 40 x = 600

100 x = 600

x = 6

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Index

9.1 - Definition and Solving Techniques
9.2 - Use of Simultaneous Linear Equations

Chapter 1