SmarterEd

Aussie Maths & Science Teachers: Save your time with SmarterEd

Measurement, STD2 M1 2014 HSC 2 MC

A measurement of  72 cm is increased by 20% and then the result is decreased by 20%. 

What is the new measurement, correct to the nearest centimetre?

  1. 46 cm
  2. 69 cm
  3. 72 cm
  4. 104 cm
Show Answers Only

`B`

Show Worked Solution
STRATEGY: Students confident in this area could save time in the calculations as follows: `72 xx 1.2 xx 0.8“ = 69.12`

`text(72 increased by 20%)`

`= 72 + (text(20%) xx 72) = 86.4\ text(cm)`

`text(86.4 decreased by 20%)`

`= 86.4\-(text(20%) xx 86.4) = 69.12\ text(cm)`

`=>  B`

Measurement, STD2 M1 2009 HSC 12 MC

How many square centimetres are in 0.0075 square metres? 

  1. 0.75 
  2. 7.5 
  3. 75
  4. 7500
Show Answers Only

`C`

Show Worked Solution

`text{Since 1 m}^2= 100\ text(cm) xx 100\ text(cm)= 10\ 000\ text{cm}^2`

 

♦♦♦ Mean mark 19%.

`:.0.0075\ text{m}^2= 0.0075 xx 10\ 000= 75\ text{cm}^2`

`=>  C`