GCSE Secondary Maths Age 13-17 - Number: Bounds - Explained

The video tutorial explains how to calculate the lower bound for the average speed of a journey. It covers the concepts of upper and lower bounds, setting up the problem with given distance and time, and performing calculations to find the bounds. The tutorial emphasizes the importance of converting units and provides a step-by-step guide to solving the problem, including calculating the average speed and ensuring the answer is correct to three significant figures.

What is the key term in the problem that indicates the type of calculation needed?

• Lower bound

• Distance

• Average speed

• Upper bound

If a distance is rounded to the nearest 5 miles, what is the lower bound for 235 miles?

• 240 miles

• 237.5 miles

• 232.5 miles

• 230 miles

How do you find the mid value between two numbers?

• Add them and multiply by two

• Subtract the smaller from the larger

• Add them and divide by two

• Multiply them together

What is the upper bound for 200 minutes rounded to the nearest 5 minutes?

• 195 minutes

• 205 minutes

• 200 minutes

• 202.5 minutes

To calculate the lower bound for average speed, which bounds do you use?

• Upper bound of distance and lower bound of time

• Upper bound of distance and upper bound of time

• Lower bound of distance and lower bound of time

• Lower bound of distance and upper bound of time

Why is it important to convert time from minutes to hours in this problem?

• To simplify the calculation

• To make the numbers smaller

• To match the units for mph

• To avoid rounding errors

What is the final answer for the lower bound of the average speed, correct to three significant figures?

• 69.0 mph

• 68.9 mph

• 70.0 mph

• 68.8 mph