WAEC Past Questions and Answers - Page 3952

19,757.

From a set \(A = [3, \sqrt{2}, 2\sqrt{3}, \sqrt{9}, \sqrt{7}]\), a number is selected at random. Find the probability that is a rational number

A.

\(\frac{1}{5}\)

B.

\(\frac{2}{5}\)

C.

\(\frac{3}{5}\)

D.

\(\frac{4}{5}\)

Correct answer is B

\(A = {3, \sqrt{2}, 2\sqrt{3}, \sqrt{9}, \sqrt{7}}\)

n(A) = 5

Let the rational nos = R

n(R) = 2 (3, \(\sqrt{9}\))

P(R) = 2/5

19,758.

In a plant of genotype Tt, what is the probability that a gamete will contain gene t?

A.

1\2

B.

3\4

C.

1\8

D.

1\6

E.

1\4

Correct answer is A

No explanation has been provided for this answer.

19,759.

If \(K\sqrt{28}+\sqrt{63}-\sqrt{7}=0\), find K.

A.

-2

B.

-1

C.

1

D.

2

Correct answer is B

\(K\sqrt{28}+\sqrt{63}-\sqrt{7}=0\)

\(2K\sqrt{7}+3\sqrt{7}-\sqrt{7}=0\)

\(2K\sqrt{7}=-2\sqrt{7}\)

\(K=\frac{-2\sqrt{7}}{2\sqrt{7}}\)

\(K=-1\)

19,760.

Simplify log\(_7\) 8 - log\(_7\) 2 + log\(_7\) 4.

A.

0

B.

\(2log_7 2\)

C.

\(3log_7 2\)

D.

\(4log_7 2\)

Correct answer is D

log\(_7\) 8 - log\(_7\) 2 + log\(_7\) 4

= log\(_7\) (8/2 x 4)

= log\(_7\) 16

= 4 log\(_7\) 2