P5-Average-L3-Ex4

Ans:

1– **432 more stamps**

Total number of stamps Jamie and Patrick had -> 360 × 2 = 720

Patrick -> 1u

Jamie -> 4u

5u –> 720 stamps

1u –> 144 stamps

4u – 1u = 3u

3 × 144 = **432 more stamps**

2– ** 71.5 kg**

Total mass of 3 boys if they weigh as much as Derek –> 75 × 3 + 12 + 9 = 246 kg

Derek’s mass –> 246 kg ÷ 3 = 82 kg

Joe’s actual mass -> 82 kg – 12 kg = 70 kg

Ron’s actual mass -> 82 kg – 9 kg = 73 kg

Average mass of Joe and Ron –> (70 + 73) ÷ 2 = **71.5 kg**

3– **5.8 m**

Total mass of the pole, plank and rod –> 4.8 m × 3 = 14.4 m

Rod –> 1u

Pole –> 2u

Plank –> 2u + 0.4 m

5u + 0.4 m -> 14.4 m

5u –> 14.4 m – 0.4 m = 14 m

Rod –> 14 m ÷ 5 = 2.8 m

Pole –> 2.8 m × 2 = 5.6 m

Plank –> 2.8 m × 2 + 0.4 = 6 m

Average length of pole and plank –> (5.6 m + 6 m ) ÷ 2 = **5.8 m**

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