GCSE Secondary Maths Age 13-17 - Ratio, Proportion & Rates of Change: Ratio - Explained

The video tutorial explains how to solve a problem involving the cost of materials for two watch faces, A and B. Both watch faces are circular with a radius of two centimeters. Watch face A is made entirely of plastic, while watch face B has a 20-degree metal sector and a 340-degree plastic sector. The cost ratio of metal to plastic is 3:2. The tutorial guides students through calculating the areas of the watch faces, determining the costs, and simplifying the ratio of costs. It concludes with advice on managing time during exams and focusing on easier questions first.

What is the main challenge in the problem involving watch faces A and B?

• Calculating the diameter of the watch faces

• Measuring the weight of the watch faces

• Finding the cost ratio of materials used

• Determining the thickness of the materials

Why is it beneficial to leave calculations in terms of π?

• It increases the cost of materials

• It helps in avoiding decimal errors

• It makes the calculations more complex

• It simplifies the process of finding the radius

How is the area of the metal part of watch face B calculated?

• By measuring the thickness of the metal

• By using the sector angle and radius

• By subtracting the plastic area from the total area

• By using the full circle area formula

What is the final ratio of the cost of materials for watch face A to B?

• 2 to 3

• 74 to 9

• 36 to 37

• 8 to 9

What advice is given regarding time management during exams?

• Ignore the marks allocated for each question

• Spend equal time on all questions

• Focus only on the challenging questions

• Prioritize easier questions first