Stage 8 Math Quiz: Percentage Increases and Decreases

Increase 250 by 12%.

• 280

• 260

• 275

• 290

Decrease 180 by 25%.

• 135

• 140

• 150

• 120

Increase 45 by 180%.

• 126

• 81

• 135

• 162

Decrease 45 by 180%.

• -36

• 0

• 36

• -81

A plant grew by 18% over the year. Its height at the start of the year was 85 cm. At the end of the year, the plant is ___ cm tall. The absolute increase is ___ cm.

• 100.3 cm, 15.3 cm

• 98 cm, 13 cm

• 102 cm, 17 cm

• 95 cm, 10 cm

A phone normally sells for 1,200. During a clearance sale, the price is reduced by 35%.

The sale price of the phone is ____.

• 780

• 800

• 850

• 900

Write the correct multiplier for each change.

Increase by 60% (a)  

Decrease by 80% (b)  

Increase by 5% (c)  

Decrease by 5% (d)  

• 1.6

• 0.2

• 0.95

• 1.05

• 1.6
• 0.2
• 1.05
• 0.95

Complete the question: Ali has $500 in his bank account. He withdraws money to buy a gaming console. His account decreased by 120%. What is his current balance?

• $100

• –$100

• –$600

• $600

A cube has side lengths of 10 cm. If each side increases by 20%,

• New volume: 1728 cm³, Percentage increase: 72.8%

• New volume: 1331 cm³, Percentage increase: 33.1%

• New volume: 2000 cm³, Percentage increase: 100%

• New volume: 1500 cm³, Percentage increase: 50%

A rectangle has a length of 15 cm and a width of 10 cm. If the area is increase by 25%, what is the new area of the rectangle?

• 200 cm²

• 250 cm²

• 187.5 cm²

• 225 cm²