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WAEC Mathematics Past Questions & Answers - Page 172

856.

Find the LCM of $2^{3}\times 3\times 5^{2}, 2\times 3^{2}\times 5 \hspace{1mm}and \hspace{1mm}2^{2}\times 3^{2}\times 5$

$2^{2}\times 3^{3}\times 5^{2}$

$2^{3}\times 3^{23}\times 5$

$2^{2}\times 3^{2}\times 5^{2}$

$2^{3}\times 3^{3}\times 5^{2}$

View answer & explanation

Correct answer is D

No explanation has been provided for this answer.

857.

Evaluate $(111_{two})^2$ and leave your answer in base 2

$111001_{two}$

$110001_{two}$

$101001_{two}$

$10010_{two}$

View answer & explanation

Correct answer is B

$(111_{two})^{2}=(111_{two})(111_{two})\\ =1 \times 2^{2}+1\times2^{1}+1\times 2^{0}=4+2+1=7_{_{ten}}\\ (111_{two})^{2}=7\times 7=49\\ \begin{matrix} 2 & 49\\ 2 & 24\hspace{1mm}R\hspace{1mm}1\\ 2 & 12\hspace{1mm}R\hspace{1mm}0\\ 2 & 6\hspace{1mm}R\hspace{1mm}0\\ 2 & 3\hspace{1mm}R\hspace{1mm}0\\ 2 & 1\hspace{1mm}R\hspace{1mm}1\\ & 0\hspace{1mm}R\hspace{1mm}1\hspace{1mm}\uparrow \end{matrix} \\ =110001_{2}$

858.

The figure shows a quadrilateral PQRS having equal sides and opposite sides parallel. The diagonals PR and QS intersect perpendicularly at O, Which of the following statements cannot be correct

|PO|=|RO|

PQR is an equilateral triangle

PQRX is a parallelogram

There are two lines of symmetry

View answer & explanation

Correct answer is B

No explanation has been provided for this answer.

859.

In the diagram, O is the center of the circle, ∠MON = 80^o, ∠LMO = 10^o and ∠LNO = 15^o. Calculate the value of x

40^o

50^o

55^o

75^o

View answer & explanation

Correct answer is C

Reflex + ∠OML + ∠ONL + ∠NLM = 360
280^o + 10^o + 15^o + x = 360^o => 305^o + x^o = 360^o
x = 360^o - 305^o = 55^o

860.

The monthly salary of a man increased from N2,700 to N3,200. Find the percentage increase

10%

15%

15.6%

18.5%

View answer & explanation

Correct answer is D

$\% increase = \frac{Increase}{initial\hspace{1mm} salary}\times 100\%\\ Increase=N3,200 - N2,700 = N500\\ Initial \hspace{1mm} salary=N2,700.00=\frac{N500}{N2,700}\times 100\% = 18.5\%$