[Moderator's note: Topics merged.]

After 20 minutes into a cross country race, Teck Seng has run 5/8 of the route while Jack has covered only 3/8 of the distance. Teck Seng runs at the same average speed throughout the race and Jack's average speed is 60 min/min slower than Teck seng's.

a) Find the total distance of the cross country race.

b) If Jack wants to finish the race at the same time as Teck Seng, by how much should he increase his average speed for the remaining part of the race? (Express your answer in m/min)[/img]

[Moderator's note: Topics merged.]


Lily is meeting a friend at a certain time.If she drives at 80km/hr, she will be 1/3 hour late. If she drives at 60km/hr, she will be 3/4 hour late. How long will the journey take if she drives at 90 km/hr?