L3 - Set 4

3 water pipes are used to fill a swimming pool. Pumps A, B, and C take 8hrs, 12hrs, and 24hrs, respectively, to fill up the pool. If all 3 pipes are opened at the same time, how long will it take to fill the pool (in hours)?

1201 contestants aged 8 to 19 joined the National Competition for Mathematics. At most how many contestants were the same age?

After flying for 5 hours, I realized that the plane I am on travels at 980km/hr. There are 450km less than the distance that we already covered left until we reach our destination. How long is the journey, in km?

We have 10 keys and 10 suitcases. At least how many attempts do we need to make in order to match each key to each correct suitcase?

What is the minimum number of straight lines needed to form 9 rectangles?

Suppose 4 spiders can build 12 webs in 10 mins. How long will it take for 16 spiders to build 24 webs?

Students from an elementary school are on a trip. Their accommodation is in the Trumpet Hotel whose number of rooms available to them is limited. If 5 students are in a room, 3 will be left out. If 4 share a room, 26 will be left out. How many students joined the trip?

9 countries donated a million dollars. What is the total amount of money they contributed?

(ANSWER HAS NO SPACE NOR COMMA)

A pipe can fill up a tank in 18hrs. A pump can empty a full tank in 20hrs. How long (in hours) will it take to fill up an empty tank if both the pipe and pump are turned on at the same time?

It takes 8 people 3 days to bake 144 cookies. How many cookies can 12 people bake in 6 days?