A Tricky 'n' Easy Maths Quiz! (5)

Answer: 3x^8 * y^2

This question was tricky. Many people often do not understand the expression because of too many brackets or powers or do a mistake while solving it. Always remember that if an expression contains brackets, solve the stuff in the brackets first. If it contains brackets within brackets, then solve the stuff in the inner brackets first.
3x^2 (y [x^3])^2
= 3x^2 (y * x^3)^2
= 3x^2 * y * x^3 * y * x^3
= 3x^2 * y^2 * x^6
= 3x^8 * y^2

Answer: £2850

Do not calculate 5% of £3000! The loss is 5% of the cost price. In other words, (100-5)% or 95% of £3000 is the selling price.
95/100 *3000 = 2850
Therefore, the selling price is £2850. Remember that a loss of 5% and a discount of 5% are the same.

Answer: infinite

A true statement containing the signs form "more than" and 'less than' is called an inequality. First we solve the inequality like an algebraic equation:
2x - 1 is less than 20
2x is less than 20 + 1
2x is less than 21
x is less than 21/2
x is less than 10 ½
This means that the solution for x is any odd number below 10 ½. There are 5 positive solutions for x and infinite negative solutions, because all negative odd numbers are smaller than 10 ½ and 5 + infinity = infinity!

Answer: 3

This is another tricky question. First we have to find the denominator. Remember that the angle representing the frequency on a pie chart is calculated by dividing the frequency by the sum of all frequencies (p) and multiplying it by 360 degrees. We know that the angle corresponding to x is 80 degrees. Therefore:
2/p * 360 = 80
2 * 360 = 80p
720 = 80p
p = 720/80
p = 9.
Now we know that the denominator or the sum of all frequencies is 9. So the missing number in the ratio is:
2 + n + 4 = 9
6 + n = 9
n = 9 - 6
n = 3.

Answer: 83.3%

When we throw an ordinary six-sided die, there are six possible scores... {1, 2, 3, 4, 5 and 6}. To find the probability of not throwing a 1 i.e throwing a 2, 3, 4, 5 or 6 is 5/6 which equals 0.833 or 83.3%.
To convert a fraction into a decimal, divide the numerator by the denominator. To convert a fraction into a percentage, multiply it by 100.

Answer: 1

Such questions are called group questions and they involve Venn Diagrams. There is a formula for such questions which is (in this case):
Total number of boys = Number of boys who like dice games + Number of boys who like card games - Number of boys who like both + Number of boys who like neither
Plug in the numbers and we get:
30 = 15 + 12 - x + 4
30 = 31 - x
30 + x = 31
x = 31 - 30
x = 1.
Therefore, only 1 boy likes both card and dice games.

Answer: 108

There is a formula for calculating the sum of the interior angles of a polygon which is (2n - 4) * 90 degrees where n is the number of sides of the polygon. A regular pentagon has 5 sides, therefore the sum of its interior angles is:
x = (2n - 4) * 90
x = (2 * 5 - 4) * 90
x = (10 - 4) * 90
x = 6 * 90
x = 540.
Now we know that the sum of all the interior angles of a regular pentagon add up to 540 degrees. Therefore, the size of one angle is (540/5) degrees or 108 degrees.

Answer: Cannot be determined

We cannot find the surface area of a cuboid unless we know its length, width and height. In this question, the cuboid's width and height is not given, therefore its surface area cannot be determined.
The formula for finding the surface area of a cuboid is:
Surface area of cuboid = 2 ([l*h] + [w*h] + [l*w]), where l is the length of the cuboid, w is the width and h is the height.
------------------------------ or -----------------------------------
Surface area of cuboid = area of face 1 + area of face 2 + area of face 3 + area of face 4 + area of face 5 + area of face 6

Answer: Cannot be determined

The size of each of the other two angles cannot be determined because:
1) We do not know what type of a triangle it is.
2) We do not know the size of at least 2 angles of that triangle.

Answer: 16

We can choose variables for Anne's, Betty's and Cathy's marks. Let a be Anne's marks, b be Betty's marks and c be Cathy's marks. We know that Anne scored 1/2 as many marks as Betty, and Betty scored 1/2 as many marks as Cathy. Therefore:
a = 1/2 b
b = 1/2 c
c = 2b
Now we can form an equation and solve:
1/2 b + 1/2 c + 2b = 112
1/2 b + b + 2b = 112
3 1/2 b = 112
b = 112/ 3 1/2
b = 112/ 7/2
b = 112* 2/7
b = 32
a = 1/2 * 32
a = 16.
Therefore, Anne scored 16 marks.
Did you enjoy this quiz and learn something new? Did you not understand my questions? Did you score less than 7? If yes, please send me a note. I'd be delighted to help you out. I accept all your corrections, ratings and suggestions. Ok then, bye bye till next time! ;)