Functions

  A plumber comes to a house to do a repair.

He charges a fixed fee of $25 plus $15 per hour.

Work out the total cost for a job that lasts 2 hours.

• 65

• 55

• 40

• 50

Answer explanation

The total cost is calculated as follows: Fixed fee of $25 + (2 hours x $15/hour) = $25 + $30 = $55. Therefore, the correct answer is 55.

A plumber comes to a house to do a repair.

He charges a fixed fee of $25 plus $15 per hour.

Write a function to show the cost in dollars (c) of a job that takes h hours.

• c = 25 + 15 * h

• c = 25 + 20 * h

• c = 30 + 15 * h

• c = 25 + 10 * h

A sunflower plant is 0.5m tall. It grows 0.1 m every week.

Work out the height after 3 weeks

• 0.7m

• 0.9m

• 1.0m

• 0.8m

Answer explanation

The sunflower starts at 0.5m and grows 0.1m each week. After 3 weeks, it grows 0.3m (0.1m x 3). So, the height after 3 weeks is 0.5m + 0.3m = 0.8m, which is the correct answer.

A sunflower plant is 0.5m tall. It grows 0.1 m every week.

How long will it take until the sunflower is 3.5m tall?

• 35 weeks

• 30 weeks

• 25 weeks

• 20 weeks

Answer explanation

The sunflower starts at 0.5m and needs to reach 3.5m, so it must grow 3.5m - 0.5m = 3m. At a growth rate of 0.1m per week, it will take 3m / 0.1m/week = 30 weeks to reach the desired height.

A sunflower plant is 0.5m tall. It grows 0.1 m every week.

   Write a function to show the height in metres (h) after t weeks.

• h = 0.5 + 0.1 * t
• h = 0.5 + 0.1 * (t + 1)
• h = 0.5 + 0.2 * t
• h = 0.5 - 0.1 * t

If x = 5 then y = 7. Which of these functions could be correct?

The cost of renting a halll is in two parts.

There is an agent's fee of $50, plus a monthly rent of $620.

Find the total cost of renting for 4 months

• $2530
• $3000
• $2000
• $2500

The cost of renting a halll is in two parts.

There is an agent's fee of $50, plus a monthly rent of $620.

The cost for m months is $r. Write a function for r.

• r = 50 + 620 * m
• r = 50 + 620 + m
• r = 50 * m + 620
• r = 50 + 600 * m

  A car has 52 litres of petrol in its tank at the start of a journey.

It uses petrol at a rate of 4 litres per hour.

    Work out how many litres are in the tank after 5 hours

• 32 litres
• 40 litres
• 28 litres
• 24 litres

  A car has 52 litres of petrol in its tank at the start of a journey.

It uses petrol at a rate of 4 litres per hour.

There are L litres in the tank after t hours. Write a formula for L.

• L = 52 - 4t
• L = 4t - 52
• L = 52 - 2t
• L = 52 + 4t