Math 2017 Question 45

Question 45

The diagram below shows the blades of a fan labelled A,B,C and D.

(a) What fraction of a turn does Blade A make if it turns in a clockwise direction to the position of Blade D? (1 mark)
(b) How many ¼ turns does Blade B make if it turns in a clockwise direction to the position of Blade D? (1 mark)
(c) Through how many degrees does Blade C turn in an anticlockwise direction to the position of Blade B? (1 mark)
(d) If Blade B travels 200 cm in in 1 whole turn, how many ½ turns will it take to make 300 cm? (2 marks)

Answer

(a) ¾

(b) 2 ¼ turns

(c) 90°

(d) three half turns

Explanation

(a) Each turn is ¼ therefore to turn three blades from A to D to ¾

(b) Each turn is ¼ therefore to turn two blades from B to D is 2 ¼ turns

(c) Note it is anticlockwise direction.  C to B is  360°÷4 =  90°

(d) One whole turn is 200 cm therefore half a turn is 200 ÷2 = 100 cm

Therefore 300 cm is one whole turn and a half turn = three half turns

OR

If a whole turn is 200 cm then a half turn is 200 ÷2 = 100 cm

Therefore Number of half turns = 300 ÷100 = 3 half turns

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