Ratio and proportion

Exchange rates

Compare pounds with dollars or euros.

Predict, test and explain

Step 1 of 3

Predict

At an illustrative rate of €1.20 per £1 with no fees, what does £50 buy?

dollars=1.2×pounds\text{dollars} = 1.2\times\text{pounds}
0501001502000100200300400US dollarsPounds

Scroll the diagram sideways to see every label.

£100.00\text{£}100.00$120.00\$120.00

InvestigateDouble the pounds. What happens to the other currency?

Explore and compare

Keep the exchange rate fixed. Double the pounds.

Try it in the simulation. Change one thing at a time.

Hint

Save the first set of values below, then double only the amount.

Notes and saved values stay in this tab. They disappear when you reload.

Hints, self-check and connections
Try a self-check

Fixed values, separate from the diagram controls.

At an illustrative rate of £1 = €1.20, with no fees, how many euros does £35 buy?

Hint

Multiply the number of pounds by the euros for each pound.

Reveal answer

€42. The rate multiplies each pound by 1.20.

35×1.20=4235\times1.20=42

Build an explanation

Hint 1

Read how much foreign currency one pound buys.

Hint 2

The graph passes through the origin because changing zero pounds gives zero currency.

Hint 3

Multiply pounds by the foreign-currency-per-pound rate; divide for the reverse conversion.

Worked example

This example uses fixed values, separate from the diagram controls.

At an illustrative rate of $1.20 for £1, how many dollars does £50 buy, with no fees?

  1. The rate gives dollars per pound.
  2. Multiply 50 by 1.20.

Answer: $60.

Connect this idea

Watch out: Check the direction of the rate before multiplying or dividing; these are illustrative rates.