JAMB Mathematics Past Questions & Answers

906.

Determine the mean monthly salary of 50 employees of a company from the following frequency distribution.
\(\begin{array}{c|c} \text{Monthly salary} & \text{Frequency}\\\hline N200.00 & 10\\ N325.00 & 5\\N100.00 & 20\\N120.00 & 2\\ N60.00 & 10\\ N80.00 & 3\end{array}\)

N215.30

N134.10

N143.10

N80.00

N50.30

View answer & explanation

Correct answer is B

\(\bar{x}\) = \(\frac{fx}{N}\)

= \(\frac{6705}{50}\)

= 1341

= N134.10

907.

Simplify f^{\(\frac{1}{2}\)}g²h^{\(\frac{1}{2}\)} \(\div\) f^{\(\frac{5}{2}\)}g^oh^{\(\frac{7}{3}\)}

(\(\frac{g}{fh}\))²

f²g²h²

\(\frac{5}{4}\)g^oh\(\frac{7}{9}\)

\(\frac{g^2}{f^5h^7}\)

\(\frac{1}{f^2h^2}\)

View answer & explanation

Correct answer is A

f^{\(\frac{1}{2}\)}g²h^{\(\frac{1}{2}\)} \(\div\) f^{\(\frac{5}{2}\)}g^oh^{\(\frac{7}{3}\)} = f^{\(\frac{1}{2}\)} - \(\frac{5}{2}\) g^{2 - 0} h\(\frac{1}{2}\) - \(\frac{7}{3}\)

f^-2 g² h^-2

= \(\frac{g^2}{f^2h^2}\)

= (\(\frac{g}{fh}\))²

908.

The square base of a pyramid of side 3cm has height 8cm. If the pyramid is cut into two parts by a plane parallel to the base midway between the base and the vertex, the volumes of the two sections are

(21cm³, 3cm³)

(24cm³, 3cm³)

(24cm³, 21cm³)

(72cm³, 9cm³)

(63cm³, 9cm³)

View answer & explanation

Correct answer is B

Vol. of the 1st section is side x height

vol. = 3 x 8

= 24cm³

vol. of the second section is 3 x 1 = 3

= 24cm³, 3cm³

909.

The area of the curved surface of the cone generated by the sector of a circle radius 6cm and arc length 22cm is (\(\pi\) = \(\frac{22}{7}\))

58 sq.cm

34 sq.cm

132 sq.cm

77 sq.cm

66 sq.cm

View answer & explanation

Correct answer is E

Given: length of the arc AOB = 22cm ; L = 6cm

Curved surface area of cone = \(\pi\)rl

Length of an arc = \(\frac{\theta}{360}\) x 2 \(\pi\)L

= 22cm

but length of an arc = circumference of the cone = 2\(\pi\)

where r is the radius of the cone circle

2\(\pi\)r = 22, r = \(\frac{22}{2\pi}\)r

= 11 x \(\frac{7}{22}\)

= \(\frac{7}{2}\)

curved surface area = \(\pi\)rl

= \(\frac{22}{7}\) x \(\frac{7}{2}\) x 6

= 66 sq.cm

910.

The solution to the simultaneous equations 3x + 5y = 4, 4x + 3y = 5 is

(\(\frac{-13}{11}, \frac{1}{11}\))

(\(\frac{13}{11}, \frac{1}{11}\))

(\(\frac{13}{11}, \frac{-1}{11}\))

(\(\frac{11}{13}, \frac{1}{11}\))

(13, 11)

View answer & explanation

Correct answer is B

3x + 5y = 4, 4x + 3y = 5

3x + 5y = 4 x 4

4x + 3y = 5 x 3

12x + 20y = 16.....(i)

12x + 9y = 15.......(ii)

subtract eqn.(ii) from eqn.(i)

11y = 1

y = \(\frac{1}{11}\)

12x + 20 x \(\frac{1}{11}\) = 16

12x = \(\frac{156}{11}\)

x = \(\frac{13}{11}\)

= \(\frac{13}{11}, \frac{1}{11}\)