definition:


Directly Proportional means: 

when one value increases, another increases at the same rate  ↑ ↑

or when one value decreases, another decreases at the same rate  ↓↓

 

example:


sale products and earn money

sale of the same product goes up, earn money goes up

sale of the same product goes down, earn money goes down

 

calculate:


A car travels 70 miles in 2 hours

How far would it travel in 5 hours?

  

 

1. step: proportion
 
: 4 hours   -    200 miles
 
* 5 hours    -       x miles
 
 
2. step: which proportion?
 
↑hours  ↑more miles = directly proportional
 
 
3. step: formula
 
x = 200 * 5
           4 
 
x = 250 miles
 
 
4. step: answer
 
It would travel 250 miles.
 

problem 1   answer


A factory makes 5 000 items in 6 hours

How many items could be made in 15 hours?

 

problem 2   answer


A small airplane can fly 660 miles in 2 hours

At this speed, how far could the airplane fly in 3 hours?

 

problem 3   answer


You can buy 4 bananas at the supermarket A for $ 1.08.

You can buy 5 of the same bananas at the supermarket B for $ 1.24

Which place is the better buy?

 

problem 4   answer


You are paid $ 24 an hour.

How much you earn in 40 hours? 

 

problem 5   answer


A factory makes 80000 items in 5 weeks

How many items could be made in 2 weeks ?

 

problem 6   answer


A car travels 70 miles in 2 hours.

How far would it travel in 5 hours?

 

problem 7  answer


You can buy 6 cakes at the supermarket A for $ 12.40.

You can buy 5 of the same cakes at the supermarket B for $ 11.20

Which place is the better buy?

 

problem 8   answer


You earn in 80 hours $ 2 240,-.

How much you are paid in 1 hour?

 

PDF-Worksheets


instructions worksheet 

 

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