IGCSE · Practice questions · Money and currency conversion

To the nearest cent.

Six original Cambridge-style questions on money: bills, change, best buys and currency conversion.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.

The method

Same currency, two decimal places.

One unit throughout: all dollars or all cents.
Exchange rate $\$1 = k$ units: multiply dollars by $k$; divide the other currency by $k$.
Sense check: does the answer have more or fewer units than you started with?
Compare prices only after changing them into the same currency.
Commission: take it off before converting, unless told otherwise.

Recall

[2 marks]

Tom buys 3 games at $\$12.99$ each. He pays with a $\$50$ note. How much change does he receive?

Cost: $3 \times 12.99 = \$38.97$. ✓
Change: $50 - 38.97 = \$11.03$. ✓

Calculation

[2 marks]

The exchange rate is $\$1 = 83.2$ rupees. (a) Change $\$250$ into rupees. (b) Change 5000 rupees into dollars.

(a) $250 \times 83.2 = 20\,800$ rupees ✓
(b) $5000 \div 83.2 = 60.096... = \$60.10$ ✓

Calculation

[2 marks]

An electricity bill is a fixed charge of $\$18.50$ plus $\$0.21$ for each unit used. Calculate the bill for 640 units.

$640 \times 0.21 = \$134.40$ ✓
$134.40 + 18.50 = \$152.90$ ✓

Analysis

[3 marks]

A watch costs $\$185$ in the USA and £150 in the UK. The exchange rate is £1 = $1.27.

In which country is the watch cheaper, and by how many dollars?

UK price in dollars: $150 \times 1.27 = \$190.50$. ✓
USA is cheaper, by $190.50 - 185 = \$5.50$. ✓

Analysis

[2 marks]

Zoo tickets cost $\$14.50$ for an adult and $\$8.75$ for a child. A family ticket for 2 adults and 3 children costs $\$52$. How much does a family of 2 adults and 3 children save by buying a family ticket?

Separate tickets: $2 \times 14.50 + 3 \times 8.75 = 29 + 26.25 = \$55.25$. ✓
Saving: $55.25 - 52 = \$3.25$. ✓

Analysis

[4 marks]

Ravi changes $\$1200$ into yen. The rate is $1 = ¥148.6, and the bank keeps 2% of the dollars as commission.

He spends ¥150 000 on holiday and changes the rest back into dollars at ¥1 = $0.0065, with no commission. How many dollars does he get back?

Dollars changed: $1200 \times 0.98 = \$1176$. ✓
Yen received: 1176 × 148.6 = ¥174 753.60. ✓
Left after spending: 174 753.60 - 150 000 = ¥24 753.60. ✓
Back to dollars: $24\,753.60 \times 0.0065 = 160.898... = \$160.90$. ✓

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