WAEC Mathematics Past Questions & Answers - Page 100

496.

Find the values of k in the equation 6k2 = 5k + 6

A.

{\(\frac{-2}{3}, \frac{-3}{2}\)}

B.

{\(\frac{-2}{3}, \frac{3}{2}\)}

C.

{\(\frac{2}{3}, \frac{-3}{2}\)}

D.

{\(\frac{2}{3}, \frac{3}{2}\)}

Correct answer is B

6k2 = 5k + 6

6k2 - 5k - 6 = 0

6k2 - 0k + 4k - 6 = 0

3k(2k - 3) + 2(2k - 3) = 0

(3k + 2)(2k - 3) = 0

3k + 2 = 0 or 2k - 3 = 0

3k = -2 or 2k = 3

k = \(\frac{-2}{3}\) or k = \(\frac{3}{2}\)

k = (\(\frac{-2}{3}\), k = \(\frac{3}{2}\))

497.

If p = (y : 2y \(\geq\) 6) and Q = (y : y -3 \(\geq\) 4), where y is an integer, find p\(\cap\)Q

A.

{3, 4}

B.

{3, 7}

C.

{3, 4, 5, 6, 7}

D.

{4, 5, 6}

Correct answer is C

p = (y : 2y \(\geq\) 6)

2y \(\leq\) 6

y \(\leq \frac{6}{2}\)

y = \(\leq\) 3

and Q = (y : y -3 \(\geq\) 4)

y - 3 \(\geq\) 4

y \(\geq\) 4 + 3

y \(\geq\) 7

therefore p = {3, 4, 5, 6, 7} and Q = {7, 6, 5, 4, 3....}

P\(\cap\)Q = {3, 4, 5, 6, 7}

498.

If 2 log x (3\(\frac{3}{8}\)) = 6, find the value of x

A.

\(\frac{3}{2}\)

B.

\(\frac{4}{3}\)

C.

\(\frac{2}{3}\)

D.

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

Correct answer is A

2 log x (3\(\frac{3}{8}\)) = 6(divide both sides by 2)

\(\frac{2 log_x(3 \frac{3}{8})}{2} = \frac{6}{2}\)

\(\log_x \frac{27}{8} = 3\)

\(\frac{27}{8} = x^3\)

\(x^3 = \frac{27}{8}\)

x = \(\sqrt{\frac{27}{8}}\)

= (\(\frac{27}{8}\))\(\frac{1}{3}\)

= \(\frac{(3^3)^{\frac{1}{3}}}{(2^3)^{\frac{1}{3}}}\)

= \(\frac{3}{2}\)

499.

Which of the following is not a probability of Mary scoring 85% in a mathematics test?

A.

0.15

B.

0.57

C.

0.94

D.

1.01

Correct answer is D

The probability not scoring 85% is = 1 - pro(scoring 85%)

= 1 - \(\frac{85}{100}\) = 1 - 0.85

= 0.15

not scoring would be less than 1

500.

The bearing of Y from X is 060o and the bearing of Z from Y = 060o. Find the bearing of X from Z

A.

300o

B.

240o

C.

180o

D.

120o

Correct answer is B

No explanation has been provided for this answer.