Proportionality and Percentages

What is the ratio between 3 and 6?

What is the ratio between 8 and 12?

• 82

• 12

• True, because there's a common number in each numerator and denominator.

Complete the following chart of inverse proportionality and find the ratio of inverse proportionality:

• k=48

  x=4

  y=6

• k=48

  x=3

  y=6

• k=48

  x=4

  y=8

• k=48

  x=3

  y=8

• k=40

  x=3

  y=8

What is the kind of proportionality between these magnitudes?

The distance a car travels and the amount of gasoline it uses.

• Direct proportionality

• Inverse proportionality

• There's no proportionality between them

Two taps take 6 hours to fill a tank. How long will it take 3 taps to fill it?

• It will take 4 hours

• It will take 2 hours

• It will take 8 hours

• It will take 12 hours

If 3 kilos of beef costs 37.5 €, how much will 5 kilos cost?

• It will cost 12.5 €

• It will cost 65 €

• It will cost 62.5 €

• It will cost 74.5 €

Three siblings are going to divide an inheritance of 100.000 € in direct proportion to their age. Their ages are: 10, 30 and 40. How much money does each of them get?

• n1 = 17500 €

  n2 = 32500 €

  n3 = 50000 €

• n1 = 13500 €

  n2 = 36500 €

  n3 = 50000 €

• n1 = 14500 €

  n2 = 35500 €

  n3 = 50000 €

• n1 = 12500 €

  n2 = 37500 €

  n3 = 50000 €