Mathematics questions and answers

Mathematics Questions and Answers

How good are you with figures and formulas? Find out with these Mathematics past questions and answers. This Test is useful for both job aptitude test candidates and students preparing for JAMB, WAEC, NECO or Post UTME.

66.

Tickets for the school play were priced at ₦520.00 each for adults and ₦250.00 each for kids. How many kids' tickets were sold if the total sales were ₦171,000.00 and there were 5 times as many adult tickets sold as children's tickets?

A.

20

B.

300

C.

50

D.

60

Correct answer is D

Let number of children's ticket at ₦250.00 each = \(x\)

∴ Number of adult tickets at ₦520.00 each = 5\(x\)

Then,

Total amount of money received from children's tickets = 250\(x\)

Total amount of money received from adult tickets = 520(5\(x\))

⇒ 250\(x\) + 520(5\(x\)) = 171,000

⇒ 250\(x\) + 2600\(x\) = 171,000

⇒ 2850\(x\) = 171,000

⇒ \(x = \frac{171,000}{2850} = 60\)

∴ 60 tickets were sold at ₦250.00 and 300 tickets were sold at ₦520.00

67.

The line \(3y + 6x\) = 48 passes through the points A(-2, k) and B(4, 8). Find the value of k.

A.

16

B.

20

C.

8

D.

-2

Correct answer is B

The line: \(3y + 6x\) = 48

Divide through by 3

⇒ y + 2\(x\) = 16

⇒ y = -2\(x\) + 16

∴ The gradient of the line = -2

The points: A(-2, k) and B (4, 8)

m =\(\frac{y2 - y1}{x2 - x1} = \frac{8 - k}{4 - (-2)}\)

⇒ m =\(\frac[8 - k}{4 + 2} = {8 - k}{6}\)

Since the line passes through the points

∴ -2 = \(\frac{8 - k}{6}\)

⇒ \(\frac{-2}[1} = \frac{8 - k]{6}\)

⇒ 8 - k = -12

⇒ k = 8 + 12

∴ k = 20

68.

Find the value of the angle marked x in the diagram above

A.

60\(^0\)

B.

45\(^0\)

C.

90\(^0\)

D.

30\(^0\)

Correct answer is A

\(PR^2 = PQ^2 + RQ^2 - 2(PQ)(RQ)cos Q\)

\(\implies cos Q = \frac{PQ^2 + RQ^2 - PR^2}{2(PQ)(RQ)}\)

\(\implies cos Q = \frac{8^2 + 5^2 - 7^2}{2\times8\times5}\)

\(\implies cos Q = \frac{64 + 25 - 49}{80}\)

\(\implies cos Q = \frac{40}{80} = 0.5\)

\(\implies Q = cos^{-1} (0.5) = 60^0\)

\(\therefore x = 60^0\)

69.

The second term of a geometric series is \(^{-2}/_3\) and its sum to infinity is \(^3/_2\). Find its common ratio.

A.

\(^{-1}/_3\)

B.

2

C.

\(^{4}/_3\)

D.

\(^{2}/_9\)

Correct answer is A

\(T_2 = \frac{-2}{3};S_\infty \frac {3}{2}\)

\(T_n = ar^n - 1\)

∴ \(T_2 = ar = \frac{-2}{3}\)---eqn.(i)

\(S_\infty = \frac{a}{1 - r} = \frac{3}{2}\)---eqn.(ii)

= 2a = 3(1 - r)

= 2a = 3 - 3r

∴ a = \(\frac{3 - 3r}{2}\)

Substitute \(\frac{3 - 3r}{2}\) for a in eqn.(i)

= \(\frac{3 - 3r}{2} \times r = \frac{-2}{3}\)

= \(\frac{3r - 3r^2}{2} = \frac{-2}{3}\)

= 3(3r - 3r\(^2\)) = -4

= 9r - 9r\(^2\) = -4

= 9r\(^2\) - 9r - 4 = 0

= 9r\(^2\) - 12r + 3r - 4 = 0

= 3r(3r - 4) + 1(3r - 4) = 0

= (3r - 4)(3r + 1) = 0

∴ r = \(\frac{4}{3} or - \frac{1}{3}\)

For a geometric series to go to infinity, the absolute value of its common ratio must be less than 1 i.e. |r| < 1.

∴ r = -\(^1/_3\) (since |-\(^1/_3\)| < 1)

70.

A rectangle has one side that is 6 cm shorter than the other. The area of the rectangle will increase by 68 cm\(^2\) if we add 2 cm to each side of the rectangle. Find the length of the shorter side

A.

15 cm

B.

19 cm

C.

13 cm

D.

21 cm

Correct answer is C

Let the length of the longer side = \(x\) cm

∴ The length of the shorter side = (\(x\) - 6) cm

If we increase each side's length by 2 cm, it becomes

(\(x\) + 2) cm and (\(x\) - 4) cm respectively

Area of a rectangle = L x B

\(A_1 = x(x - 6) = x^2 - 6x\)

\(A_2 = (x + 2)(x - 4) = x^2 - 4x + 2x - 8 = x^2 - 2x - 8\)

\(A_1 + 68 = A_2\) (Given)

⇒ \(x^2 - 6x + 68 = x^2 - 2x - 8\)

⇒ \(x^2 - x^2 - 6x + 2x\) = -8 - 68

⇒ -4\(x\) = -76

⇒ \(x\) = \(\frac{-76}{-4}\) = 19cm

∴ The length of the shorter side = \(x\) - 6 = 19 - 6 = 13 cm