WAEC Mathematics Past Questions & Answers - Page 232

1,156.

Solve the inequality 2x + 3 < 5x

A.

\(x>1\)

B.

\(x<\frac{3}{7}\)

C.

\(x>\frac{3}{7}\)

D.

\(x>-1\)

Correct answer is A

2x + 3 < 5x
-3x < -3
X > 1

1,157.

A survey shows that 28% of all the men in a village wear size 9 shoes. What is the probability that a man selected at random in the village wears size 9 shoes?

A.

\(\frac{7}{25}\)

B.

\(\frac{41}{50}\)

C.

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

D.

1

Correct answer is A

P(man picked at random wears size 9 shoes) = \(\frac{28}{100}\)

= \(\frac{7}{25}\)

1,158.

The root of a quadratic equation in x, are -m and 2n. Find the equation

A.

\(x^2 + x(m - 2n)-2mn=0\)

B.

\(x^2 - x(m - 2n)-2mn=0\)

C.

\(x^2 - x(m - 2n)+2mn=0\)

D.

\(x^2 + x(m - 2n)+2mn=0\)

Correct answer is A

x = -m \(\implies\) x + m = 0;

x = 2n \(\implies\) x - 2n = 0.

\(\implies (x + m)(x - 2n) = 0\)

\(x^2 + mx - 2nx - 2mn = 0\)

\(x^2 + x(m - 2n) - 2mn = 0\)

1,159.

If \(x^2 +15x + 50 = ax^2 + bx + c = 0\). Which of the following statement is not true?

A.

x = -5

B.

x = 10

C.

x + 10 = 0

D.

bc = 750

Correct answer is B

\(x^2 + 15x + 50 = 0\)

\(x^2 + 5x + 10x + 50 = 0\)

\(x(x + 5) + 10(x + 5) = 0\)

\((x + 5)(x + 10) = 0\)

x + 5 = 0 or x + 10 = 0.

Comparing \(x^2 + 15x + 50\) with \(ax^2 + bx + c\), b = 15 and c = 50.

\(\therefore\) bc = 750.

1,160.

Which of the following pairs of inequalities is represented on the number line?

A.

\(x<-2 and x\ge1\)

B.

\(x\ge -2 and x>1\)

C.

\(x\le -2 and x\ge1\)

D.

\(x< -2 and x>1\)

Correct answer is C

No explanation has been provided for this answer.