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JAMB Mathematics Past Questions & Answers - Page 177

881.

If the function y = 5x is graphed, what would be its intercept on the y-axis?

$\frac{1}{5}$

zero

View answer & explanation

Correct answer is E

y = 5x, when x = 0

y = 0, when x = 1

y = 5

intercept on y axis is 0

882.

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

883.

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

884.

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

885.

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