Help With Upper & Lower Bounds

[tomtomtom1]

Hi all

I am studying for a maths test regarding upper and lower bounds, i have found a list of questions which i have attempted, i wa hoping someone could confirm if my answers are correct.

1. The weight of a bag of potatoes is 25 kg, correct to the nearest kg.
(a) Write down the smallest possible weight of the bag of potatoes (My answer = 24.5kg)
(b) Write down the largest possible weight of the bag of potatoes (My answer = 25.5kg)

2. The length of a line is 63 centimetres, correct to the nearest centimetre.
(a) Write down the least possible length of the line (My answer = 62.5cm)
(b) Write down the greatest possible length of the line (My answer =63.5cm )

3. A field is in the shape of a rectangle.
The length of the field is 340 m, to the nearest metre.
The width of the field is 117 m, to the nearest metre.
Calculate the upper bound for the perimeter of the field (My answer = 916m)

4. The length of a rectangle is 30 cm, correct to 2 significant figures.
The width of a rectangle is 18 cm, correct to 2 significant figures.
(a) Write down the upper bound of the width (My answer = I DO NOT KNOW)
(b) Calculate the upper bound for the area of the rectangle (My answer = I DO NOT KNOW)

5.The length of the rectangle is 35 cm correct to the nearest cm.
The width of the rectangle is 26 cm correct to the nearest cm.
Calculate the upper bound for the area of the rectangle (My answer = 940.75)

 

[HallsofIvy]

Those are all correct, except, of course, for 4. You appear to be saying you do not know what "significant figures" means. If problem 4 had said "30 cm to the nearest cm" and "18 cm to the nearest cm" would you be able to do it?

 

[tomtomtom1]

I would, the answer would be 29.5cm- 30.5cm & 17.5cm - 18.5cm,