NECO Mathematics Past Questions & Answers - Page 21

101.

Divide the LCM of 15abc and 20a\(^2\)bc by their HCF

A.

10a

B.

12a

C.

5abc

D.

12a2bc

E.

60a2bc

Correct answer is B

LCM of 15abc and 20a\(^2\)bc = 60a\(^2\)bc

Factors of 15abc = 1, 3, 5,15, a, b, c     

and of  20a\(^2\)bc = 1, 2, 4, 5, 10, 20, a, b, c

HCF of 15abc and 20a\(^2\)bc = 5abc

→ LCM ÷ HCF = 60a\(^2\)bc ÷ 5abc

= 12a

102.

Simplify \((216{\frac{1}{3}})^{-2}\)

A.

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

B.

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

C.

\(\frac{1}{13}\)

D.

\(\frac{1}{6}\)

E.

\(\frac{1}{3}\)

Correct answer is A

\((216^{\frac{1}{3}})^{-2}\)

= \(216^{\frac{-2}{3}}\)

= (3√216)\(^{-2}\)

= (6)\(^{-2}\)

= \(\frac{1}{6^2}\) 

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

103.

The expression 4x2 - 4 has the following as its factors EXCEPT

A.

x - 1

B.

x + 1

C.

x2 -1

D.

4x + 1

E.

4x - 4

Correct answer is D

No explanation has been provided for this answer.

104.

Calculate (0.05 × 0.025) ÷ (4.25 × 3.35) and express your answer in standard form

A.

8.7796 × 105

B.

8.7796 × 104

C.

8.7796 × 103

D.

8.7796 × 10-3

E.

8.7796 × 10-5

Correct answer is E

No explanation has been provided for this answer.

105.

The angle subtended by a diameter of a circle at the circumference is a/an

A.

acute angle

B.

obtuse angle

C.

reflex angle

D.

right angle

E.

supplementary angle

Correct answer is D

No explanation has been provided for this answer.