P and Q run along a circular track in 4 minutes and 7 minutes respectively. They start from the
same point at the same time. When Q has completed 12 rounds, how many times will they
meet if they run in, (i) Same direction, (ii) Opposite directions?
A) (i) 9, (ii) 33 B) (i) 9, (ii) 12
C) (i) 6, (ii)18 D) (i) 9, (ii) 8
Answers
Answer:
9 & 33 Times
Step-by-step explanation:
P run along a circular track in 4 minutes
Q run along a circular track in 7 minutes
Let say Track one round length = R
P speed = R/4
Q speed = R/7
1. they run in same direction
P runs faster so p will meet Q when he has done 1 circular round extra
Let say after T min they meet
=> T(R/4) = R + T(R/7)
=> T ( R/4 - R/7) = R
=> T (3R) = 28R
=> T = 28/3 mins
Every 28/3 mins they meet once
Q completes 12 rounds in 12 * 7 = 84 mins
Number of times they meet = (84/28/3) = 9
9 Times
2. in opposite direction
They Meet together when they have have completed one circular round together
=> T(R/4) + T(R/7) = R
=> T 11R = 28R
=> T = 28/11 mins
Every 28/11 mins they meet
Q completes 12 rounds in 12 * 7 = 84 mins
Number of times they meet = (84/28/11) = 33
33 Times