Numbers
what is the reciprocal of 20?
1/20
Simplify: 2(x+3)− 4(x−1)
−2x+10
2(3x−5)−(4x−7)
2x−3
What is the sum of the exterior angles of a 15-sided polygon?
360°
Which doesn't belong: 36, 64, 49, 81, 90
90 (not a perfect square)
A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball.
How much does the ball cost?
$0.05
Two pens and three pencils cost £2.50.
Three pens and two pencils cost £3.
Find the cost of one pen and one pencil.
pencil = 0.30
Pen = 0.80
The sum of two numbers is 30. Their difference is 4. What are the numbers?
17 and 13
A triangle has legs of 5 cm and 12 cm. Find the hypotenuse.
13
Think of a number. Double it, add 8, divide by 2, subtract 4. What’s the result?
the original number
A machine produces 1 item every 17 seconds. How many items can it produce in 3 hours?
635 items
The perimeter of a rectangle is 40 cm. The length is 4 cm more than the width.
What are the dimensions?
width = 8 cm
length = 12 cm
Jane is 3 years older than twice her brother’s age. Together they are 33 years old.
How old is Jane?
23
A trapezium has parallel sides 6 cm and 10 cm, height 4 cm. What is the area?
32 cm2
Pick a 3-digit number where the hundreds and units digits differ by 5.
Reverse the digits.
Subtract the smaller number from the larger.
What’s the middle digit of your answer?
Always 9.
I am a number.
I am less than 100.
My digits multiply to 36.
My digits add up to 13.
What number am I?
49 → 4 × 9 = 36, 4 + 9 = 13
Factorise completely: 3x2 - 12x + 12
3(x−2)2
The product of two consecutive integers is 132.What are the integers?
x=−12, -11 or x=12, 11
In a circle, angle at the centre is twice the angle at the circumference from the same arc.
If the angle at the centre is 110°, what’s the angle at the circumference?
55°
A woman drank 5 glasses of iced tea in a row at a party.
A man drank only one.
All the drinks were poisoned, yet only the man died.
Why?
The poison was in the ice.
The woman drank quickly before it melted; the man sipped slowly.
What’s the next number: 2, 6, 12, 20, ?
30
A number is increased by 5, and the result is multiplied by 3. The final answer is the same as if the number had first been multiplied by 3 and then increased by 15. What is the number?
Any real number will work — infinitely many solutions.
Find the midpoint of the line segment connecting the points A(2, 5) and B(8, –3).
(5,1)
A cube and a sphere have the same volume of 343 cm³.
What is the side length of the cube?
7 cm
RAPID FIRE: You must answer as many questions (correctly) to earn these 400 points in 2 minutes