JAMB Mathematics Past Questions & Answers - Page 158

786.

What is the greatest straight line distance between two vertices (corners) of a cube whose sides are 2239cm long?

A.

\(\sqrt{2239cm}\)

B.

\(\sqrt{2}\) x 2239cm

C.

\(\frac{\sqrt{3}}{2}\) 2239cm

D.

\(\sqrt{3}\) x 2239cm

E.

4478cm

Correct answer is D

x = \(\sqrt{-2239^2 + 2239^2}\)

= -\(\sqrt{10026242}\)

= 3166.42

y = -\(\sqrt{10026242 + 5013121}\)

= -\(\sqrt{15039363}\)

= 3878

= \(\sqrt{3}\) x 2239

787.

An arc of circle of radius 2cm subtends an angle of 60º at the centre. Find the area of the sector

A.

\(\frac{2 \pi}{3}\)cm2

B.

\(\frac{\pi}{2}\)cm2

C.

\(\frac{\pi}{3}\)cm2

D.

\(\pi\)cm2

Correct answer is A

Area of a sector \(\frac{\theta}{360}\) x \(\pi\)r\(^2\)

= \(\frac{60^o}{360^o}\) x \(\pi\)2\(^2\)

= \(\frac{2 \pi}{3}\)cm2

788.

A cylinder of height h and radius r is open at one end. Its surface area is

A.

2\(\pi\)rh

B.

\(\pi\)r2h

C.

2\(\pi\)rh + \(\pi\)r2

D.

2\(\pi\)rh + 2\(\pi\)r2

Correct answer is C

A cylinder of height h ans radius r is open at one end, its surface area is 2\(\pi\)rh + \(\pi\)r2

789.

Simplify \(\frac{1 - x^2}{x - x^2}\), where x \(\neq\) 0

A.

\(\frac{1}{x}\)

B.

\(\frac{1 - x}{x}\)

C.

\(\frac{1 + x}{x}\)

D.

\(\frac{1}{x - 1}\)

E.

\(\frac{-x - 1}{1}\)

Correct answer is C

\(\frac{1 - x^2}{x - x^2}\), where x = \(\neq\) 0

\(\frac{1^2 - x^2}{x - x^2}\)

= \(\frac{(1 + x)(1 - x)}{x(1 - x)}\)

= \(\frac{1 + x}{x}\)

790.

For the set of numbers 2, 3, 5, 6, 7, 7, 8

A.

The median is greater than the mode

B.

The mean is greater than the mode

C.

The mean is greater than the median

D.

The median is equal to the mean

E.

The mean is less than the median

Correct answer is E

Mean = 5, 42

Median = 6

Mode = 7

The mean is less than the median