Question

Please help with this question

Answer 1

Answer:

a) t = 4000/v

b) t = 4000/(v + 20)

c) see attached workings

Step-by-step explanation:

a)  A man jogs 4 km everyday at an average speed of v m/min

As the speed is measured in meters per minute, we need to convert the distance (4 km) into meters:

    1 km = 1000 m

⇒ 4 km = 4 x 1000 = 4000 m

   distance = speed x time

⇒ time = distance / speed

⇒ t = 4000/v  (where t = time in minutes)

b) If his average speed increased by 20 m/min, then his speed would now be  (v + 20) m/min

⇒ t = 4000/(v + 20)  (where t = time in minutes)

c) Given the man would take 3 min less if his average speed increased by 20 m/min, we can rewrite the second equation as:

t - 3 = 4000/(v + 20)

Now simply substitute the first equation t = 4000/v into the second:

(I have typed this used MS Word and attached, as the equation editor here in Brainly is not working at the moment).