Level 3
The figure shows two identical semi-circles. XY is a straight line. X and Y are the centres of the semi-circles. Given that the radius of the semi-circle is 10 cm, find the area of the shaded regions. Express the answer correct to 1 decimal place. (Take π = 3.14)
3 m
Level 3
This figure is not drawn to scale. A rectangular glass tank 72 cm by 50 cm by 35 cm has 2 compartments, X and Y, with a water height of 30 cm in X and 15 cm in Y. A hole in the slider caused water to leak from X to Y. It was found that the water level in both compartments became the same after some time.
  1. What is the height of water in the tank now?
  2. It took 112 h for the water in both compartments to reach the same level. Assuming that water leaked at a constant rate, how much water flowed from X to Y in 1 minute? Express the answer to 1 decimal place in cm³.
4 m
Level 3
The figure is made of 2 quadrants and a rectangle. The rectangle measures 12 cm by 4 cm. Using the calculator value of π, find the area of the shaded part. Correct the answer to 2 decimal places.
3 m
Level 3
A tank is to be filled to the brim. Tap A takes 20 minutes to fill the tank while Tap B takes 15 minutes to fill it. How long will it take to completely fill the tank with water if both the taps are turned on at the same time? Leave the answer in minutes and round off to 1 decimal place.
4 m
Level 3
It takes Faucet X 15 minutes to fill a tank measuring 14 cm by 8 cm by 12 cm completely while it takes Faucet Y only 10 minutes. How long will it take to completely fill the tank with water if both faucets are turned on at the same time and 3 cubic cubes of edges 3 cm, filled with water, are poured into the tank? Leave the answer in minutes and round off to 2 decimal places.
4 m
Level 3
Study the patterns.
  1. Find the total number of triangles in Figure 30.
  2. Express the biggest triangle as a percentage of the total possible number of triangles in Figure 30. Correct your answer to 2 decimal places.
5 m
Level 3
Vincent has some 20-cent coins and 50-cent coins which amount to more than $20 but less than $54. The number of 20-cent coins is 14 of all the coins he has. When he exchanges some 50-cent coins for 20-cent coins, the ratio of the number of 50-cent coins to 20-cent coins he now has become 1 : 6.
  1. What is the largest possible amount of money Vincent has?
  2. What is the total value of 50-cent coins that has been exchanged for 20-cent coins? Express the answer to 2 decimal place.
5 m
Level 3
The figure is made up of a big semicircle of diameter 8 cm and 2 small semicircles with diameter 5.7 cm. Find the shaded area. Round off the answer to nearest 1 decimal place. (Take π = 3.14)
4 m
Level 3
Willi noticed the patterns on the square tiles and tried to calculate the area of the shaded part. Leave the answer in 2 decimal places. (Take π = 3.14)
4 m
Level 3
Copier A prints at a rate of 105 leaflets in every 3 minutes and Copier B prints at a rate of 136 leaflets in every 4 minutes. At 2 p.m., both copiers started printing. After a while, Copier A stopped printing for some time as the ink cartridges were being changed before it continued to print again. Copier B continued printing during this time. At 4 p.m., the total number of leaflets printed during the past two hours was 7930. Express the number of leaflets printed by Copier A as a percentage of the total number of leaflets printed by both copiers. Round off the answer to 2 decimal places.
5 m