WAEC Past Questions and Answers - Page 1162

5,806.

Find the constant term in the binomial expansion of \((2x - \frac{3}{x})^{8}\).

A.

90720

B.

1296

C.

1120

D.

672

Correct answer is A

\((x)^{n}(x^{-1})^{8 - n} = x^{0}\)

\(x^{n} . x^{-8 + n} = x^{0} \implies n - 8 + n = 0\)

\(2n - 8 = 0 \implies n = 4\)

Constant term = \(^{8}C_{4}(2^{4})(3^{4}) = 70 \times 16 \times 81\)

= \(90720\)

5,807.

The total of the discount from creditors is transferred to

A.

Credit side of discounts received account

B.

Debit side of discounts received account

C.

Credit side of discounts allowed account

D.

Debit side of discounts allowed account

Correct answer is A

No explanation has been provided for this answer.

5,808.

Find the values of x at the point of intersection of the curve \(y = x^{2} + 2x - 3\) and the lines \(y + x = 1\).

A.

(1, -2)

B.

(0, 4)

C.

(2, -3)

D.

(1, -4)

Correct answer is D

Equate the equation of the curve and the line in order to find their point of intersection ie The values of y in both equations. 

\(y + x = 1 \implies y = 1 - x\)

\(x^{2} + 2x - 3 = 1 - x\)

\(x^{2} + 2x + x - 3 - 1 = 0 \implies x^{2} + 3x - 4 = 0\)

\((x - 1)(x + 4) = 0\)

\(x = (1, -4)\)

5,809.

If P(x - 3) + Q(x + 1) = 2x + 3, find the value of (P + Q).

A.

0

B.

1

C.

2

D.

3

Correct answer is C

No explanation has been provided for this answer.

5,810.

A fair die is tossed twice. Find the probability of obtaining a 3 and a 5.

A.

\(\frac{5}{12}\)

B.

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

C.

\(\frac{1}{18}\)

D.

\(\frac{1}{36}\)

Correct answer is D

P(c and e) = \(P(c) \times P(e)\)

P(3) = \(\frac{1}{6}\)

P(5) = \(\frac{1}{6}\)

P(3 and 5) = \frac{1}{6} \times \frac{1}{6} = \frac{1}{36}\)