Percentage (part 2)

The number 2400 is first increased by 30%. The value obtained is next decreased by 20%. Find the final number!

Answer explanation

2400 x 30% = 720

2400 + 720 = 3120

3120 x 20% = 624

3120 - 624 = 2496

Every year, the value of a condominium in Singapore appreciates by 15% of its value in the previous year. If the value of the condominium was $899300 in 2020, find its value in 2018!

Answer explanation

2020 = 899300

2019 x 115% = 899300

2019 = 899300 x 100/115

2019 = 782000

2018 x 115% = 782000

2018 = 782000 x 100/115

2018 = 680000

Every year, the value of a surveying machine depreciates by 25% of its value in the previous year. If the value of the machine was $11250 in 2019, fine its value in 2017!

Answer explanation

2019 = 11250

2018 x (100%-25%) = 11250

2018 x 75% = 11250

2018 = 11250 x 100/75

2018 = 15000

2017 x 75% = 15000

2017 = 15000 x 100/75

2017 = 20000

If 10% is deducted from a bill, $58.50 remains to be paid. How much is the original bill?

Answer explanation

Bill x (100%-10%) = 58.50

Bill x 90% = 58.50

Bill = 58.50 x 100/90

Bill = 65

Ali is 8% taller than Yi Hao and Vani is 10% shorter than Yi Hao. Express Ali's height as a percentage of Vani's height!

Answer explanation

Supposed Yi Hao's height is 100cm, then Ali's height is 108 and Vani's height is 90 cm

Ali/Vani x100% = 108/90 x100% = 120%