WAEC Past Questions and Answers - Page 1005

5,021.

Rent paid during 1995 was N2,000 while rent paid at 31st December, 1995 was

A.

N2,400

B.

N2,200

C.

N2,000

D.

N1,800

E.

N200

Correct answer is D

No explanation has been provided for this answer.

5,022.

The double entries for refund of unsuccessful application monies are, debit

A.

Application for shares account, credit bank account

B.

Bank account, credit application for shares account

C.

Allotment account, credit application for shares account

D.

Allotment account, credit bank account

E.

Cash account, credit bank account

Correct answer is A

No explanation has been provided for this answer.

5,023.

If \((x - 5)\) is a factor of \(x^3 - 4x^2 - 11x + 30\), find the remaining factors.

A.

\((x + 3) and (x - 2)\)

B.

\((x - 3) and (x + 2)\)

C.

\((x - 3) and (x - 2)\)

D.

\((x + 3) and (x + 2)\)

Correct answer is A

(x - 5) is a factor of \(x^3 - 4x^2 - 11x + 30\). To find the remaining factors, let's draw out \((x - 5)\) from the parent expression.

\(x^3 - 4x^2 - 11x + 30 = x^3 - 5x^2 + x^2 - 5x - 6x + 30\)

\(= x^2(x - 5) + x(x - 5) - 6(x - 5) = (x - 5)(x^2 + x - 6)\)

∴ To find the remaining factors, we factorize \((x2 + x - 6)\)

\(x^2 + x - 6 = x^2 + 3x - 2x - 6\)

\(= x(x + 3) - 2(x + 3) = (x + 3)(x - 2)\)

∴ The other two factors are \((x + 3) and (x - 2)\)

ALTERNATIVELY
\(∴ x^2 + x - 6 = (x + 3) and (x - 2)\)

5,024.

In how many ways can four Mathematicians be selected from six ?

A.

90

B.

60

C.

15

D.

360

Correct answer is C

\(=^6C_4\)

\(=\frac{6!}{(4!\times2!)}\)

\(=\frac{6\times5}{2\times1}\)

= 15

5,025.

Find the coefficient of the \(6^{th}term\) in the binomial expansion of \((1 - \frac{2x}{3})10\) in ascending powers of \(x\).

A.

\(-\frac{896x^6}{9}\)

B.

\(-\frac{896x^5}{9}\)

C.

\(-\frac{896x^5}{27}\)

D.

\(-\frac{896x^6}{27}\)

Correct answer is C

rth term of a binomial expansion =\(^nC_r-1 a^{n-(r-1)}b^{r-1}\)

\(n = 10,r = 6 \therefore r-1=5\)

6th term =\(^{10}C_5 1^{10} - 5 (-\frac{2}{3}x)^5\)

\(=252*1*-\frac{32x^5}{243}=-\frac{896x^5}{27}\)