b) Which of the following relationships are true a nd which are false? [l marks)

Question

b) Which of the following relationships are true a nd which are false? [l marks) [I marks] [1 marks] 12 marks] (i) 7 12 (ii) 13 > -5 (iv)-4-4 [2 marks] 12 marks] (vi) -7.4 .72 [2 marks) 4 Simnlifv: mnlity ovities will tfillin 7 minutes? If a runner takes 56 minutes to run 8 km, how long will it take to finish a 20 km race? 12 marks] [2 marks] If 4 men complete a job in 10 hours, how long will it take 5 men to complete the same job? 2 marks] (v) A rowing boat finished a race of 8 km at a speed of 20km/h. How long did it [2 take to complete the race? marks] A car travelling at a steady speed takes 6 hours to travel 492 km. What was the (v) [2 marks] speed of the car? Page 1 of 4

Explanation / Answer

B)

(i) false

(ii) true

(iii)true

(iv)false

(v)false

(vi)false - both are equal

(i)false - both are equal

Simplify

(ii) as 8 km in 56 minutes - so, for 1 km he will take 7 mins

so, for 20 km runner will take 20 * 7 =140 minutes -

= 2 hours 20 mins

(iii) 4 men take 10 hours - so, if 1 man does - he will take 4 * 10 = 40 hours

so, if it is done by 5 men - it will be 40/5 = 8 hrs

(iv) time taken in rowing = distance travelled / speed

= 8/20 = 2/5 hours

= 24 minutes

(v) Speed of car = distance / time taken

= 492/6

= 82 kmph

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