JustDoingMath's answer to Raya's Primary 6 Maths Speed Singapore question.
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Without using Algebra :
40km/h x 3h = 120km
120km refers to the distance between Kenny and Sheldon in the 2 hours when Sheldon was ahead.
Since Sheldon drove 120km in the 2 hours he was ahead of Kenny , we can use the formula speed = distance / time , so Sheldon’s speed = 120km / 2h = 60km/h
Using Algebra :
Let Sheldon’s speed be y.
Kenny’s speed would be (y+40)
Since Kenny took only 3 hours to catch up to Sheldon driving 5 hours ,
5y = 3(y+40)
5y = 3y+120
2y = 120
y = 60
Therefore , Sheldon’s speed is 60km/h.
40km/h x 3h = 120km
120km refers to the distance between Kenny and Sheldon in the 2 hours when Sheldon was ahead.
Since Sheldon drove 120km in the 2 hours he was ahead of Kenny , we can use the formula speed = distance / time , so Sheldon’s speed = 120km / 2h = 60km/h
Using Algebra :
Let Sheldon’s speed be y.
Kenny’s speed would be (y+40)
Since Kenny took only 3 hours to catch up to Sheldon driving 5 hours ,
5y = 3(y+40)
5y = 3y+120
2y = 120
y = 60
Therefore , Sheldon’s speed is 60km/h.
Date Posted:
2 years ago
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