Year : 
1997
Title : 
Mathematics (Core)
Exam : 
JAMB Exam

Paper 1 | Objectives

31 - 40 of 45 Questions

# Question Ans
31.

In a triangle XYZ, if < ZYZ is 60, XY = 3cm and YZ = 4cm, calculate the length of the sides XZ.

A. √23cm

B. √13cm

C. 2√5cm

D. 2√3cm

Detailed Solution

(XZ)2 = 32 + 42 - 2 x 3 x 4 cos60o

= 25 - 24\(\frac{1}{2}\)

XZ = √13cm
32.

Differentiate \(\frac{6x^3 - 5x^2 + 1}{3x^2}\) with respect to x

A. \(\frac{2 + 2}{3x^3}\)

B. 2 + \(\frac{1}{6x}\)

C. 2 - \(\frac{2}{3x^3}\)

D. \(\frac{1}{5}\)

Detailed Solution

\(\frac{6x^3 - 5x^2 + 1}{3x^2}\)

let y = 3x2

y = \(\frac{6x^3}{3x^2}\) - \(\frac{6x^2}{3x^2}\) + \(\frac{1}{3x^2}\)

Y = 2x - \(\frac{5}{3}\) + \(\frac{1}{3x^2}\)

\(\frac{dy}{dx}\) = 2 + \(\frac{1}{3}\)(-2)x-3

= 2 - \(\frac{2}{3x^3}\)
33.

\(\frac{d}{dx}\) cos(3x\(^2\) - 2x) is equal to

A. -sin(6x - 2)

B. -sin(3x2 - 2x)dx

C. (6x - 2) sin(3x2 - 2x)

D. -(6x - 2)sin(3x2 - 2x)

Detailed Solution

Let \(3x^{2} - 2x = u\)
\(y = \cos u \implies \frac{\mathrm d y}{\mathrm d u} = - \sin u\)
\(\frac{\mathrm d u}{\mathrm d x} = 6x - 2\)
\(\therefore \frac{\mathrm d y}{\mathrm d x} = (6x - 2) . - \sin u\)
= \(- (6x - 2) \sin (3x^{2} - 2x)\)
34.

Integrate \(\frac{1}{x}\) + cos x with respect to x

A. -\(\frac{1}{x^2}\) + sin x + k

B. x + sin x - k

C. x - sin x + k

D. -\(\frac{1}{x^2}\) - sin x + k

Detailed Solution

\(\int \frac{1}{x} + \cos x = ln x - \sin x + k\)
35.

If \(y = x(x^4 + x + 1)\), evaluate \(\int \limits_{0} ^{1} y \mathrm d x\).

A. \(\frac{11}{12}\)

B. 1

C. \(\frac{5}{6}\)

D. zero

Detailed Solution

\(y = x(x^{4} + x + 1) = x^{5} + x^{2} + x\)
\(\int \limits_{0} ^{1} (x^{5} + x^{2} + x) \mathrm d x = \frac{x^{6}}{6} + \frac{x^{3}}{3} + \frac{x^{2}}{2}\)
= \([\frac{x^{6}}{6} + \frac{x^{3}}{3} + \frac{x^{2}}{2}]_{0} ^{1}\)
= \(\frac{1}{6} + \frac{1}{3} + \frac{1}{2}\)
= \(1\)
36.

\(\begin{array}{c|c} Age & 20 & 25 & 30 & 35 & 40 & 45\\
\hline Number of people & 3 & 5 & 1 & 1 & 2 & 3\end{array}\)
Find the median age of the frequency distribution in the table above.

A. 20

B. 25

C. 30

D. 35

B

37.

Find the difference between the range and the variance of the following set of numbers 4, 9, 6, 3, 2, 8, 10, 5, 6, 7 where \(\sum d^2\) = 60

A. 2

B. 3

C. 4

D. 6

Detailed Solution

Range : 10 - 2 = 8
Variance = \(\frac{\sum d^{2}}{n}\)
= \(\frac{60}{10}\)
= 6
8 - 6 = 2.
38.

In a basket of fruits, there are 6 grapes, 11 bananas and 13 oranges, if one fruit is chosen at random, what is the probability that the fruit is either a grape or a banana?

A. \(\frac{17}{30}\)

B. \(\frac{11}{30}\)

C. \(\frac{6}{30}\)

D. \(\frac{5}{30}\)

Detailed Solution

Pgrape or Pbanana = \(\frac{6}{30}\) + \(\frac{11}{30}\)

= \(\frac{17}{30}\)
39.

A number is selected at random between 10 and 20, both numbers inclusive. Find the probability that the number is an even number

A. \(\frac{5}{11}\)

B. \(\frac{1}{2}\)

C. \(\frac{6}{11}\)

D. \(\frac{7}{10}\)

Detailed Solution

n(even numbers between 10 and 20 inclusive) = 6
n(numbers between 10 and 20) = 11
P(even) = \(\frac{6}{11}\)
40.

Find the standard derivation of the following data -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5

A. 2

B. 3

C. \(\sqrt{10}\)

D. \(\sqrt{11}\)

Detailed Solution

x = \(\frac{\sum x}{N}\)

= \(\frac{0}{11}\)

= 0

\(\begin{array}{c|c} x & (x - x) & (x - x)^2 \\\hline -5 & -5 & 25 \\ -4 & -4 & 16 \\-3 & -3 & 9 \\ -2 & -2 & 4 \\ -1 & -1 & 1\\ 0 & 0 & 0\\ 1 & 1 & 1\\ 2 & 2 & 4\\ 3 & 3 & 9\\ 4 & 4 & 16 \\5 & 5 & 25\\ \hline & & 110\end{array}\)
S.D = \(\sqrt{\frac{\sum(x - x)^2}{\sum f}}\)

= \(\sqrt{\frac{110}{11}}\)

= \(\sqrt{10}\)
31.

In a triangle XYZ, if < ZYZ is 60, XY = 3cm and YZ = 4cm, calculate the length of the sides XZ.

A. √23cm

B. √13cm

C. 2√5cm

D. 2√3cm

Detailed Solution

(XZ)2 = 32 + 42 - 2 x 3 x 4 cos60o

= 25 - 24\(\frac{1}{2}\)

XZ = √13cm
32.

Differentiate \(\frac{6x^3 - 5x^2 + 1}{3x^2}\) with respect to x

A. \(\frac{2 + 2}{3x^3}\)

B. 2 + \(\frac{1}{6x}\)

C. 2 - \(\frac{2}{3x^3}\)

D. \(\frac{1}{5}\)

Detailed Solution

\(\frac{6x^3 - 5x^2 + 1}{3x^2}\)

let y = 3x2

y = \(\frac{6x^3}{3x^2}\) - \(\frac{6x^2}{3x^2}\) + \(\frac{1}{3x^2}\)

Y = 2x - \(\frac{5}{3}\) + \(\frac{1}{3x^2}\)

\(\frac{dy}{dx}\) = 2 + \(\frac{1}{3}\)(-2)x-3

= 2 - \(\frac{2}{3x^3}\)
33.

\(\frac{d}{dx}\) cos(3x\(^2\) - 2x) is equal to

A. -sin(6x - 2)

B. -sin(3x2 - 2x)dx

C. (6x - 2) sin(3x2 - 2x)

D. -(6x - 2)sin(3x2 - 2x)

Detailed Solution

Let \(3x^{2} - 2x = u\)
\(y = \cos u \implies \frac{\mathrm d y}{\mathrm d u} = - \sin u\)
\(\frac{\mathrm d u}{\mathrm d x} = 6x - 2\)
\(\therefore \frac{\mathrm d y}{\mathrm d x} = (6x - 2) . - \sin u\)
= \(- (6x - 2) \sin (3x^{2} - 2x)\)
34.

Integrate \(\frac{1}{x}\) + cos x with respect to x

A. -\(\frac{1}{x^2}\) + sin x + k

B. x + sin x - k

C. x - sin x + k

D. -\(\frac{1}{x^2}\) - sin x + k

Detailed Solution

\(\int \frac{1}{x} + \cos x = ln x - \sin x + k\)
35.

If \(y = x(x^4 + x + 1)\), evaluate \(\int \limits_{0} ^{1} y \mathrm d x\).

A. \(\frac{11}{12}\)

B. 1

C. \(\frac{5}{6}\)

D. zero

Detailed Solution

\(y = x(x^{4} + x + 1) = x^{5} + x^{2} + x\)
\(\int \limits_{0} ^{1} (x^{5} + x^{2} + x) \mathrm d x = \frac{x^{6}}{6} + \frac{x^{3}}{3} + \frac{x^{2}}{2}\)
= \([\frac{x^{6}}{6} + \frac{x^{3}}{3} + \frac{x^{2}}{2}]_{0} ^{1}\)
= \(\frac{1}{6} + \frac{1}{3} + \frac{1}{2}\)
= \(1\)
36.

\(\begin{array}{c|c} Age & 20 & 25 & 30 & 35 & 40 & 45\\
\hline Number of people & 3 & 5 & 1 & 1 & 2 & 3\end{array}\)
Find the median age of the frequency distribution in the table above.

A. 20

B. 25

C. 30

D. 35

B

37.

Find the difference between the range and the variance of the following set of numbers 4, 9, 6, 3, 2, 8, 10, 5, 6, 7 where \(\sum d^2\) = 60

A. 2

B. 3

C. 4

D. 6

Detailed Solution

Range : 10 - 2 = 8
Variance = \(\frac{\sum d^{2}}{n}\)
= \(\frac{60}{10}\)
= 6
8 - 6 = 2.
38.

In a basket of fruits, there are 6 grapes, 11 bananas and 13 oranges, if one fruit is chosen at random, what is the probability that the fruit is either a grape or a banana?

A. \(\frac{17}{30}\)

B. \(\frac{11}{30}\)

C. \(\frac{6}{30}\)

D. \(\frac{5}{30}\)

Detailed Solution

Pgrape or Pbanana = \(\frac{6}{30}\) + \(\frac{11}{30}\)

= \(\frac{17}{30}\)
39.

A number is selected at random between 10 and 20, both numbers inclusive. Find the probability that the number is an even number

A. \(\frac{5}{11}\)

B. \(\frac{1}{2}\)

C. \(\frac{6}{11}\)

D. \(\frac{7}{10}\)

Detailed Solution

n(even numbers between 10 and 20 inclusive) = 6
n(numbers between 10 and 20) = 11
P(even) = \(\frac{6}{11}\)
40.

Find the standard derivation of the following data -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5

A. 2

B. 3

C. \(\sqrt{10}\)

D. \(\sqrt{11}\)

Detailed Solution

x = \(\frac{\sum x}{N}\)

= \(\frac{0}{11}\)

= 0

\(\begin{array}{c|c} x & (x - x) & (x - x)^2 \\\hline -5 & -5 & 25 \\ -4 & -4 & 16 \\-3 & -3 & 9 \\ -2 & -2 & 4 \\ -1 & -1 & 1\\ 0 & 0 & 0\\ 1 & 1 & 1\\ 2 & 2 & 4\\ 3 & 3 & 9\\ 4 & 4 & 16 \\5 & 5 & 25\\ \hline & & 110\end{array}\)
S.D = \(\sqrt{\frac{\sum(x - x)^2}{\sum f}}\)

= \(\sqrt{\frac{110}{11}}\)

= \(\sqrt{10}\)