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WAEC Mathematics Past Questions & Answers - Page 167

831.

A fair coin is tossed three times. Find the probability of getting two heads and one tail.

$\frac{1}{2}$

$\frac{3}{8}$

$\frac{1}{4}$

$\frac{1}{8}$

View answer & explanation

Correct answer is B

Pr(head) = $\frac{1}{2}$ , Pr(tail) = $\frac{1}{2}$ :Pr(2 heads)

= $\frac{1}{2}$ x $\frac{1}{2}$ = $\frac{1}{4}$

Pr(2 heads and tail) 3 times

= ( $\frac{1}{4}$ x $\frac{1}{2}$ ) x 3

= $\frac{3}{8}$

832.

P is a point on the same plane with a fixed point A. If P moves such that it is always equidistant from A, the locus of P is

a straight line joining A and P

the perpendicular bisector of AP

a circle with centre A

the triangle with centre P

View answer & explanation

Correct answer is C

No explanation has been provided for this answer.

833.

Given that y = 1 - $\frac{2x}{4x - 3}$ , find the value of x for which y is undefined

$\frac{3}{4}$

$\frac{-3}{4}$

-3

View answer & explanation

Correct answer is B

for undefined expression, the denomination is zero 4x - 3 = 0

4x = 3; x = $\frac{3}{4}$

834.

Simplify $\frac{x - 4}{4} - \frac{x - 3}{6}$

$\frac{x - 18}{12}$

$\frac{x - 6}{12}$

$\frac{x - 18}{24}$

$\frac{x - 6}{24}$

View answer & explanation

Correct answer is B

$\frac{x - 4}{4} - \frac{x - 3}{6}$ = $\frac{3(x - 4) - 2(x - 3)}{12}$

= $\frac{3x -12 - 2x + 6}{12}$

= $\frac{3x - 2x - 12 + 6}{12}$

= $\frac{x - 6}{12}$

835.

Simplify $\frac{25 ^\frac{2}{3} \div 25 ^\frac{1}{6}}{( \frac{1}{5})^{-\frac{7}{6}} \times ( \frac{1}{5})^{\frac{1}{6}}}$

$\frac{1}{5}$

$\frac{1}{25}$

View answer & explanation

Correct answer is C

$\frac{25 \frac{2}{3} \div 25 \frac{1}{6}}{( \frac{1}{5})^{-\frac{7}{6}} \times ( \frac{1}{5})^{\frac{1}{6}}}$ = $\frac{25^{4 - \frac{1}{6}}}{(\frac{1}{5})^{-7 + \frac{1}{6}}}$

= $\frac{25^{\frac{1}{2}}}{(\frac{1}{5})^{-1}}$

= $\frac{(5^2)^{\frac{1}{2}}}{(5^{-1})^{-1}}$

= $\frac{5}{5}$

= 1