WAEC Mathematics Past Questions & Answers - Page 193

961.

The locus of points equidistant from two intersecting straight lines PQ and PR is

A.

a circle centre P radius Q.

B.

a circle centre P radius PR

C.

the point of intersection of the perpendicular bisectors of PQ and PR

D.

the bisector of angle QPR

Correct answer is C

No explanation has been provided for this answer.

962.

The probabilities of a boy passing English and Mathematics test are x and y respectively. Find the probability of the boy failing both tests

A.

1-(x-y)+xy

B.

1-(x+y)-xy

C.

1-(x+y)+xy

D.

1 - (x - y) + x

Correct answer is C

Prob (passing English) = x
Prob (passing Maths) = Y
Prob (failing English) = 1 - x
Prob (failing Maths) = 1 - y
Prob (failing both test) = Prob(failing English) and Prob(failing Maths) = (1 - x)(1 - y)
=1 - y - x + xy
=1 - (y + x) + xy

963.

Given that p varies as the square of q and q varies inversely as the square root of r. How does p vary with r?

A.

p varies as the square of r

B.

p varies as the square root of r

C.

p varies inversely as the square of r

D.

p varies inversely as r

Correct answer is D

\(p \propto q^2\)

\(q\propto\frac{1}{\sqrt{r}}\)

\(p = kq^2\)

\(q = \frac{c}{\sqrt{r}}\)

where c and k are constants.

\(q^2 = \frac{c^2}{r}\)

\(p = \frac{kc^2}{r}\)

If k and c are constants, then kc\(^2\) is also a constant, say z.

\(p = \frac{z}{r}\)

p varies inversely as r.

964.

The square root of a number is 2k. What is half of the number

A.

\(\sqrt{\frac{k}{2}}\)

B.

\(\sqrt{k}\)

C.

\(\frac{1}{2}k^2\)

D.

2k2

Correct answer is D

Let the number be x.

\(\sqrt{x} = 2k \implies x = (2k)^2\)

= \(4k^2\)

\(\frac{1}{2} \times 4k^2 = 2k^2\)

965.

From the Venn Diagram below, find Q' ∩ R.

A.

(e)

B.

(c, h)

C.

(c, g, h)

D.

(c, e, g, h)

Correct answer is C

Q' ∩ R Q' = U - Q Q' = {a, b, c, d, g, h, i} R = {c, e, h, g} Q' ∩ R = {c, h, g}