smc-893-25-% increase/decrease

Number, NAP-K4-NC06 SA

Michael purchases a 3D printer worth $2 490 000.

He was given a 10% discount.

What was the price paid by Michael after the discount?

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`$2\ 241\ 000`

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`text(Discount)`	`= 10% xx 2\ 490\ 000`
	`= $249\ 000`

`:.\ text(Price)`	`= 2\ 490\ 000 – 249\ 000`
	`= $ 2\ 241\ 000`

Number, NAP-A4-CA14

The population of Australian states in 2015 and 2016 is recorded in the table below.

Some data for Western Australia is not shown.

What was the population of Western Australia (WA) close to in 2016?

`2\ 773\ 100`	`2\ 710\ 500`	`2\ 147\ 600`	`2\ 091\ 300`

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`2\ 091\ 300`

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`text(WA Population in 2016)`

`= 2\ 085\ 021 xx 1.003`

`~~ 2\ 091\ 300`

Number, NAP-B4-NC27

A tennis racquet costs $95.

A tax of 10% is added to the price.

Which calculation will give the new price?

`95 + 10`	`95 + 0.1`	`95 xx 0.1`	`95 xx 1.1`

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`95 xx 1.1`

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`text(New price)`	`=95 + (10text{%} xx 95)`
	`=95 + 0.1 xx 95`
	`=95 xx 1.1`

Number, NAP-J4-CA35 SA

The original price of a refrigerator is $3200.

Saroo buys the refrigerator at a sale for 20% off the original price.

He has a discount voucher that gives him a further $64 off the sale price.

What percentage of the original price does Saroo pay for the refrigerator?

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`text(78%)`

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`text(Sale price)`	`= 80text(%) xx $3200`
	`= $2560`

`text(Purchase price)`	`= 2560 – 64`
	`= $2496`

`text(Percentage of original price)`

`= 2496/3200 xx 100`

`= 78text(%)`

Number, NAP-J4-CA26 SA

A locksmith increases the price of replacing a key from $12 to $15.

What is the percentage increase her fee?

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`text(25%)`

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`text(Price increase) = 15 – 12 = $3`

`text(Percentage increase)`	`= 3/12`
	`= 0.25`
	`= 25text(%)`

Number, NAP-B4-CA15

Jake bought a mobile phone at 25% off the original price.

The original price was $380.

How much did Jake pay for the mobile phone?

`$95`	`$285`	`$342`	`$355`

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`$285`

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`text(Price of mobile)`	`=380 – (text(25%) xx 380)`
	`=380 – 95`
	`=$285`

Number, NAP-F4-CA06

James weighed 80 kg when he was 18 years old.

On his 21st birthday, James weighs 5% more than when he was 18.

How much does he weigh now?

`76\ text(kg)`	`84\ text(kg)`	`85\ text(kg)`	`120\ text(kg)`

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`84\ text(kg)`

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`80 + (80 xx 5text{%})`	`= 80 + 4`
	`= 84\ text(kg)`

Number, NAP-G4-CA18

Marty and Paul swam 3 km in an ocean swimming race.

Marty finished in a time of 1 hour and 10 minutes.

Paul took 25% longer than Marty.

Approximately how long did Paul take to finish the race?

`88\ text(minutes)`	`95\ text(minutes)`	`135\ text(minutes)`	`138\ text(minutes)`

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`88\ text(minutes)`

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`text(Paul’s time)`

`= (1\ text{hour and 10 minutes)} xx text(125%)`

`= 70 xx text(125%)`

`= 87.5\ text(minutes)`

`:.\ text(88 minutes is the closest choice.)`

Number, NAP-H4-CA27

A dress was on sale with 25% discount.

As a regular customer, Kate received a further 10% on the already discounted price.

What was the overall percentage discount Kate received?

`text(2.5%)`	`text(12.5%)`	`text(27.5%)`	`text(32.5%)`	`text(35%)`

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`text(32.5%)`

Show Worked Solution

`text(Let the dress cost) = $100`

`text(C) text(ost after 25% discount) = $75`

`text(C) text(ost after another 10% discount)`

`= 75 – (10 text{%} xx 75)`

`= $67.50`

`:.\ text(Overall discount) = 32.5text(%)`

Number, NAP-I4-NC28 SA

Angus bought a tennis racket which cost $22.50 before the Goods and Services Tax (GST) was added.

How much did Angus' tennis racket cost after adding the 10% GST?

`$`

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`$24.75`

Show Worked Solution

`text(C)text(ost)`	`= 22.50 + 10text(%) xx 22.50`
	`= 22.50 + 2.25`
	`= $24.75`