Comparing Quantities
Discount and tax
Work out a discount, a sale price, and the price once tax has been added.
A marked price is what the label says. A discount is a percentage taken off it, and what is left is the sale price. Tax works the same way in reverse: a percentage of the price is worked out and added on. Both are just percentages of an amount, which you have done for years — the only new part is keeping straight which amount the percentage is of.
Always ask: a percentage of what?
A discount is a percentage of the marked price. Tax is a percentage of the price after any discount. So when a shop takes 10 per cent off and then adds 10 per cent tax, you do not get back to where you started — the tax is worked out on a smaller amount, so you finish slightly below the marked price.
Worked example
A coat is marked ₹1500 with a discount of 20 per cent. What do you pay?
Find 20 per cent of 1500: one tenth is 150, so two tenths is 300.
Working through 10 per cent is almost always faster than multiplying by 0.2, and it is easier to check.
Try it together
Now let us price a ₹2400 cycle with a discount of 15 per cent and then tax of 5 per cent.
Discount first, tax second, because the tax is charged on what you actually pay.
1.What is 15 per cent of 2400?
Have a go
Have a go on your own: a table is marked ₹5000 with a discount of 12 per cent. What is the sale price? Give just the number.
Hint: Find one per cent of 5000 first, then twelve of them, then take that off.
Ready to practise?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.