. When a man weighing SO Kg ru.ns at an average speed of 10 Km1r, his rate of energy dissipation is four times higher than when he runs at an average speed of 3 Km hr. However, when a 60 Kg man runs at 12 Km hr: his rate of energy dissipation is only three times higher than when he runs at an average speed of 6 km hr. If a man walks at 4 mph over a certain journey and jogs back over the same route at 6 mph at an altitude of 200 meters. What is his average speed for the jou.rney in mph?

O 6.00

O 2.40

O 120.00

O 4.80

• Average speed = 4*6*2/(4+6) = 24/10 = 4.8 mph
• 12 years agoHelpfull: Yes(9) No(3)
• (d)
  the above 4 lines are rubbish............we need not to consider height
  rest use the formulae 2xy/(x+y)
  hence 48/10=4.8
  hence (d) is answer ..........
• 12 years agoHelpfull: Yes(7) No(0)
• The first two lines are given to confuse yourself and the real question starting from third line itself and the formula for this question is 2xy/x+y. so the answer is 4.80
• 12 years agoHelpfull: Yes(2) No(1)