Real-life questions from the kitchen: scaling recipes up and down, how much of each ingredient and cooking times. Read the story, work it out and type the answer.
Pasta needs 12 minutes to cook. It has been cooking for 3 minutes. How many more minutes does it need?
Twice as many people: double every amount.
Half as many people: halve every amount.
Any other number: find the amount for 1 person, then multiply.
1000 g = 1 kg
Cooking times: add each part on, or work backwards from when it must be ready.
Time by weight: count the lots of 500 g (or 1 kg), multiply, then add any extra time.
A ratio of 1 : 4 means 1 part for every 4 parts, so 5 parts in all.
For twice as many people, double every amount; for half as many, halve it. For any other number, find the amount for 1 person first, then multiply. A recipe for 4 with 200 g of flour has 50 g a person, so 6 people need 6 × 50 g = 300 g.
Count how many lots of the weight there are, multiply by the time for each, then add any extra time. A 2 kg chicken at 20 minutes for every 500 g plus 20 minutes is 4 × 20 + 20 = 100 minutes, which is 1 hour 40 minutes.
Work backwards from when the food must be ready. Take away the cooking time, jumping back to the o'clock first. For dinner at 6:00 PM with 1 hour 15 minutes in the oven, the food goes in at 4:45 PM.
A ratio of 1 : 4 means 1 part of one thing for every 4 parts of the other, so 5 parts in all. For 500 mL of squash mixed 1 : 4, one part is 500 ÷ 5 = 100 mL: 100 mL of squash and 400 mL of water.