Nurses need to calculate the drip rate, D, in drops per minute for infusions.

They use the formula D = \(\frac{dv}{60n}\) ,where d is the drop factor measured in drops per millilitre (mL),

v is the volume in mL of the infusion, and

n is the number of hours the infusion is required to run.

A nurse wants to double the time an infusion runs for.

Describe precisely how D changes if n is doubled but d and v do not change.

Nurses also need to calculate the volume of the infusion, v, from the drip rate, D.

An infusion with a drip rate of 50 drops per minute has to be given to a patient for 3 hours. For this infusion the drop factor is 25 drops per millilitre.

What is the volume in mL of the infusion?

Ninety-five percent of world trade is moved by sea, by roughly 50 000 tankers, bulk carriers and container ships. Most of these ships use diesel fuel.
Engineers are planning to develop wind power support for ships. Their proposal is to attach kite sails to ships and use the wind’s power to help reduce diesel consumption and the fuel’s impact on the environment.

One advantage of using a kite sail is that it flies at a height of 150 m. There, the wind speed is approximately 25% higher than down on the deck of the ship.
At what approximate speed does the wind blow into a kite sail when a wind speed of 24 km/h is measured on the deck of the ship?

You are making your own dressing for a salad.
Here is a recipe for 100 millilitres (mL) of dressing.

Salad oil= 60 ml
Vinegar= 30 ml
Soy Sauce = 10 ml

How many millilitres (mL) of salad oil do you need to make 150 mL of this dressing?

Mount Fuji is only open to the public for climbing from 1 July to 27 August each year. About 200 000 people climb Mount Fuji during this time.
On average, about how many people climb Mount Fuji each day?

The Gotemba walking trail up Mount Fuji is about 9 kilometres (km) long.

Walkers need to return from the 18 km walk by 8 pm.

Toshi estimates that he can walk up the mountain at 1.5 kilometres per hour on average, and down at twice that speed. These speeds take into account meal breaks and rest times.

Using Toshi’s estimated speeds, what is the latest time he can begin his walk so that he can return by 8 pm?

Toshi wore a pedometer to count his steps on his walk along the Gotemba trail.

His pedometer showed that he walked 22 500 steps on the way up.

Estimate Toshi’s average step length for his walk up the 9 km Gotemba trail. Give your answer in centimetres (cm).

On one trip, Helen rode 4 km in the first 10 minutes and then 2 km in the next 5 minutes.
Which one of the following statements is correct?

Helen rode 6 km to her aunt’s house. Her speedometer showed that she had averaged 18 km/h for the whole trip.
Which one of the following statements is correct?

Helen rode her bike from home to the river, which is 4 km away. It took her 9 minutes. She rode home using a shorter route of 3 km. This only took her 6 minutes.
What was Helen’s average speed, in km/h, for the trip to the river and back?
Average speed for the trip: