Math Mastery Online Series 1

A* Master Class

Practice

1. Viola had 25

as many apples as Queenie at first. Viola bought another 8 apples and

Queenie ate 5 apples. Then, Viola had 45

as many apples as Queenie. Find the number of apples Viola had at first.

2. During Taylor Swift’s concert, 14

of the audience left at the first interval to use the toilet.

24 of them came back. Then, another 49

of the audience rushed out to buy merchandise. After a while, 160 of them came back. In the end, there were 1755 people left in the concert hall. How many people were at the concert at first?

Math Mastery Online Series 2

3. An equal number of men and woman took part in a survey. 40% of men wear glasses while 68% of all who wear glasses are women. What percentage of women wear glasses?

4. In the quadrilateral 𝐴𝐵𝐶𝐷, ∠𝐴𝐵𝐶 = 90°, ∠𝐵𝐴𝐷 = 70°, and 𝐴𝐵 = 𝐵𝐷 = 𝐵𝐶. Find ∠𝐵𝐷𝐶.

Math Mastery Online Series 3

5. What is the value of 𝑥?

6. The figure below shows a shaded region 𝐶𝐺𝐷 in a rectangle 𝐴𝐶𝐸𝐺 . Given that 𝐴𝐵 = 𝐴𝐻 = 𝐵𝐶 = 𝐶𝐷 and 𝐶𝐷 is twice of 𝐷𝐸, what fraction of the figure is shaded?

Math Mastery Online Series 4

7. The average height of a group of children is 124 cm. If 35

of the children are boys and

their average height is 126 cm, find the average height of the girls.

8. Daryl takes four days to repair 10 cars and 24 motorcycles. He takes six days to repair 12 cars and 48 motorcycles. What is the maximum number of motorcycles Daryl can repair in 5 days?

Time Taken (in days) Cars repaired Motorcycles repaired

Math Mastery Online Series 5

9. Frank and Ben each bought some sheets of paper from a bookstore. If Frank and Ben used 40 and 80 sheets of paper each day, respectively, Frank would have 500 sheets of paper left when Ben runs out of paper. If Frank and Ben used 80 and 40 sheets of paper each day, respectively, Frank would have 20 sheets of paper left when Ben runs out of paper. How many sheets of paper did they have altogether?

Math Mastery Online Series 6

Critical Thinking Time!

1. There are some red, white, blue, pink and yellow balls in a bag. Peter is blindfolded and asked to pick 1 ball at a time from the bag. At least how many balls must Peter pick to ensure he will have 4 balls of the same colour?

2. A group of 38 farmers harvested mangoes on a farm. Each man plucked 14 kg of mangoes while each woman plucked 11 kg. The women plucked 232 kg less mangoes than the men. How many women were there?

Math Mastery Online Series 7

3. During the COVID-19 outbreak, a Singaporean travelled overseas on a business trip. A Ministry of Health inspector questioned 4 suspects. Each of them made declarations as follows:

Andrea: “I was at home all day, every day.” Bryan: “Andrea posted a photo on Facebook at Changi Airport.” Claire: “Bryan is lying.” Dylan: “Bryan travelled overseas.”

Given that only 1 declaration was true, who should be quarantined?

Assume Bryan is the culprit.

Assume Andrea is the culprit.