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Can anyone pls tell me when do we cross multiply and when do we multiply 10 * 75 im really confused

Can anyone pls tell me when do we cross multiply and when do we multiply 10 * 75 im-example-1
User BKF
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6.1k points

1 Answer

3 votes

You don't multiply liters of gasoline by distance.

They are directly proportional - the more gasoline you have the longer is the dictance you can go.

So it's cross multiply.

Another examlpe:

you are paid by hour for your work. The more hours you have worked, the more you are paid:

hours payment

2 h $36

5 h x


x=\frac{5\cdot36}2=90

You would multiply 10•70 if they were inversely poportional values

For example:

1. speed and time of ride by given distance {the greater the speed the less time you need for a ride}

speed time

10 m/s 75 s

8 m/s x


x=(10\cdot75)/(8)=93.75\,s

2. price and kolos of apples - the higher the pice the less of kilos you can buy by given cash

price kilos of apples

$2 8

$4 x


x=(2\cdot8)/(4)=4\,kg

User Mustaq
by
6.7k points
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