JAMB Mathematics Past Questions & Answers - Page 169

841.

Three numbers, x, y and z are connected by the relationships y = \(\frac{4x}{9}\) + 1. If x = 99, Find z = \(\frac{4y}{9}\) + 1

A.

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

B.

20

C.

21

D.

176\(\frac{4}{9}\)

E.

None of the above

Correct answer is C

y = \(\frac{4x}{9}\) + 1, z = \(\frac{4y}{9}\) + 1, z = \(\frac{4}{9}\)(\(\frac{4}{9}\) x + 1) + 1

= [\(\frac{4}{9}\)(\(\frac{4}{9}\)(99) + 1]

= \(\frac{4}{9}\)(45) + 1

= 21

842.

Which of the formula below represents the general terms of the following set of numbers(-1, \(\frac{2}{3}\), -\(\frac{1}{2}\), \(\frac{2}{5}\)......) for n = 1, 2, 3, 4.......?

A.

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

B.

(-1)n + 1 \(\frac{2}{n + 1}\)

C.

(-1)n \(\frac{2}{n + 1}\)

D.

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

E.

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

Correct answer is C

(-1, \(\frac{2}{3}\), -\(\frac{1}{2}\), \(\frac{2}{5}\)......)

nthterm is (-1)n\(\frac{2}{n + 1}\)

Since (-1)n will always be negative for n = odd

843.

What factor is common to all the expressions x2 - x, 2x2 + x - 1 and x2 - 1?

A.

x

B.

x + 1

C.

x - 1

D.

No common factor

E.

(2x - 1)

Correct answer is D

x2 - x = x(x - 1)

= 2x2 + x - 1

= (2x - 1)(x + 10

x2 - 1 = (x + 1)(x - 1)

No factor

844.

Make c the subject of formula v = 1 - \(\frac{a}{5}\)(b + \(\frac{3c}{7}\))

A.

[\(\frac{7}{3}\) + \(\frac{5}{a}\)(v - 1)] + b

B.

[\(\frac{7b}{3}\) + \(\frac{5}{a}\)(v - 1)]

C.

\(\frac{7}{3}\)[b + \(\frac{5}{a}\)(v - 1)]

D.

\(\frac{7}{3}\)[b + \(\frac{5v - 1}{a}\)]

Correct answer is A

No explanation has been provided for this answer.

845.

Simplify \(\frac{log_{10}8}{log_{10}4}\)

A.

log102

B.

log104

C.

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

D.

2

E.

None of the above

Correct answer is C

\(\frac{log_{10}8}{log_{10}4}\) = \(\frac{log_{10}2^3}{log_{10}2^2}\)

= \(\frac{3 log_{10}2}{2log_{10}2}\)

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