iGCSE Mathematics (0580) :E1.10 Give appropriate upper and lower bounds.iGCSE Style Questions Paper 2

Question

The distance between two towns is 600 km, correct to the nearest 10 km.
A car takes 8 hours 40 minutes, correct to the nearest 10 minutes, to travel this distance.

Calculate the lower bound for the average speed of the car in km/h.

▶️ Answer/Explanation

Solution

68 km/h

Lower bound distance = 595 km (600-5)

Upper bound time = 8h 45m = 8.75 hours

Lower bound speed = 595 ÷ 8.75 = 68 km/h

Question

(a) A bag of rice has a mass of 25kg, correct to the nearest kilogram.
Calculate the lower bound of the total mass of 10 of these bags.

(b) Virat has 200 metres of wire, correct to the nearest metre.
He cuts the wire into n pieces of length 3 metres, correct to the nearest 20 centimetres.
Calculate the largest possible value of n.

▶️ Answer/Explanation

Answer:

(a) 245 kg

(b) 69

Explanation:

(a) Lower bound per bag = 24.5kg (nearest kg). For 10 bags: 24.5 × 10 = 245kg.

(b) Max wire length = 200.5m, min piece length = 2.9m (nearest 20cm). Largest n = 200.5 ÷ 2.9 ≈ 69.13 → 69 full pieces.

iGCSE Mathematics (0580) :E1.10 Give appropriate upper and lower bounds.iGCSE Style Questions Paper 2

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