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What is a formula?

A formula is a special type of equation that links two or more physical variables.

P = 2(l + w)

P represents the perimeter of a rectangle

l stands for the length of the rectangle

w symbolizes the rectangle’s width.

We can use this formula to work out the perimeter of any rectangle given its length and width.

We do this by substituting known values into the formula.

w

l

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Speed, distance and time

If a car travels 2 km in 1 min 40 secs, at what speed is the car travelling?

Write the distance and the time using the correct units before substituting them into the formula.

S = d

t

S =2000100

= 20 m/s

Use the formula:

2 kilometres = 2000 metres1 min and 40 secs = 100 seconds

Write the units in as the final step in the calculation.

Now substitute these numerical values into the formula.

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Adding numbers to formulae

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Van hire

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Van hire

I need a van for 5 days and I will be doing 1000 miles. Which company will be cheaper?

Can you find values for d and m where the cost is the same for both firms? How did you work this out?

What’s the maximum mileage I can do in one day in a Green Getters van before I spend £75?