Mathematics JAMB, WAEC, NECO AND NABTEB Official Past Questions

778

(a) Given that \(\sin \alpha = 0.3907\), use tables to find the value of : (i) \(\tan \alpha\) ; (ii) \(\cos \alpha\).

(b) A ladder of length 4.5m leans against a vertical wall making an angle of 50° with the horizontal ground. If the bottom of a window is 4m above the ground, what is the distance between the top of the ladder and the bottom of the window? (Answer correct to the nearest cm)

View Answer & Discuss WAEC 1988
779

In the diagram, < PQR = < PSQ = 90°, |PS| = 9 cm, |SR| = 16 cm and |SQ| = x cm.

(a) Find the value of x using a trigonometric ratio.

(b) Calculate : (i) the size of < QRS to the nearest degree; (ii) |PQ|.

View Answer & Discuss WAEC 1988
780

The number of items produced by a company over a five- year period is given below:

Year 1978 1979 1980 1981 1982
No produced 4100 2500 1500 1800 9200

(i) Plot a bar chart for this information; (ii) What is the average production for the five- year period.

 

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781

(a) Derive the smallest equation whose coefficients are integers and which has roots of \(\frac{1}{2}\) and -7. 

(b) Three years ago, a father was four times as old as his daughter is now. The product of their present ages is 430. Calculate the ages of the father and daughter. 

View Answer & Discuss WAEC 1989
782

(a) Triangle PQR is right-angled at Q. PQ = 3a cm and QR = 4a cm. Determine PR in terms of a. 

(b) Ayo travels a distance of 24km from X on a bearing of 060° to Y. He then travels a distance of 18km to a point Z  and Z is 30km from X.

(i) Draw the diagram to show the positions of X, Y and Z ; (ii) What is the bearing of Z from Y ; (iii) Calculate the bearing of X from Z.

View Answer & Discuss WAEC 1989
783

(a) A pair of fair dice each numbered 1 to 6 is tossed. Find the probability of getting a sum of at least 9.

(b) If the probability that a civil servant owns a car is \(\frac{1}{6}\), find the probability that:

(i) two civil servants, A and B, selected at random each owns a car ; (ii) of two civil servants, C and D selected at random, only one owns a car ; (iii) of three civil servants, X, Y and Z, selected at random, only one owns a car.

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784

(a) In an A.P, the difference between the 8th and 4th terms is 20 and the 8th term is \(1\frac{1}{2}\) times the 4th term. What is the:

(i) common difference ; (ii) first term of the sequence?

(b) The value of a machine depreciates each year by 5% of its value at the beginning of that year. If its value when new on 1st January 1980 was N10,250.00, what was its value in January 1989 when it was 9 years old? Give your answer correct to three significant figures.

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785

(a) (i) Prove that the angle which an arc of a circle subtends at the centre is twice that which it subtends at any point on the remaining part of the circumference.

(ii) In the diagram above, O is the centre of the circle and PT is a diameter. If < PTQ = 22° and < TOR = 98°, calculate < QRS.

(b) ABCD is a cyclic quadrilateral and the diagonals AC and BD intersect at H. If < DAC = 41° and < AHB = 70°, calculate < ABC.

View Answer & Discuss WAEC 1989
786

When a stone is thrown vertically upwards, its distance d metres after t seconds is given by the formula \(d = 60t – 10t^{2}\). Draw the graph of \(d = 60t – 10t^{2}\) for values of t from 1 to 5 seconds using 2cm to 1 unit on the t- axis and 2cm to 20 units on the d- axis.

(a) Using your graph, (i) how long does it take to reach a height of 70 metres? (ii) determine the height of the stone after 5 seconds. (iii) after how many seconds does it reach its maximum height.

(b) Determine the slope of the graph when t = 4 seconds.

View Answer & Discuss WAEC 1989
787

(a) 

In the diagram, O is the centre of the circle radius 3.2cm. If < PRQ = 42°, calculate, correct to two decimal places, the area of the:

(i) minor sector POQ ; (ii) shaded part.

(b) If the sector POQ in (a) is used to form the curved surface of a cone with vertex O, calculate the base radius of the cone, correct to one decimal place.

View Answer & Discuss WAEC 1989
788

(a) If \(\cos \alpha = 0.6717\), use mathematical tables to find (i) \(\alpha\) ; (ii) \(\sin \alpha\)

(b) The angle of depression of a point P on the ground, from the top T of a building is 23.6°. If the distance of P from the foot of the building is 50m, calculate the height of the building, correct to the nearest metre.

View Answer & Discuss WAEC 1989
789

Using a ruler and a pair of compasses only, construct a triangle ABC, given that |AB| = 8.4cm, |BC| = 6.5cm and < ABC = 30°. Construct the locus: 

(a) \(l_{1}\) of points equidistant from AB and BC, and within the angle ABC;

(b) \(l_{2}\) of points equidistant from B and C. Locate the point of intersection P of \(l_{1}\) and \(l_{2}\). Measure |AP|. 

View Answer & Discuss WAEC 1989
790

The diagram shows a wooden structure in the form of a cone, mounted on a hemispherical base. The vertical height of the cone is 24cm and the base height 7cm. Calculate, correct to three significant figures, the surface area of the structure. [Take \(\pi = \frac{22}{7}\)].

View Answer & Discuss WAEC 1989
791

The table shows the weights, to the nearest kilogram, of twelve students in a Further Mathematics class

Weight in kg 55 57 59 61 63
No of students 2 1 2 4 3

(a) Draw a bar chart to illustrate the above information;

(b) What is (i) the mode; (ii) the median of the distribution?

(c) Calculate the mean weight correct to the nearest kilogram.

 

View Answer & Discuss WAEC 1989
792

(a) Without using Mathematical tables, find x, given that \(6 \log (x + 4) = \log 64\)

(b) If \(U = {1, 2, 3,4, 5, 6, 7, 8, 9, 10}, X = {1, 2, 4, 6, 7, 8, 9}, Y = {1, 2, 3, 4, 7, 9}\) and \(Z = {2, 3, 4, 7, 9}\). What is \(X \cap Y \cap Z’ \)?

View Answer & Discuss WAEC 1989
793

An aeroplane flies from a town P(lat. 40°N, 38°E) to another town Q(lat. 40°N, 22°W). It later flies to a third town T(28°N, 22°W). Calculate the :

(a) distance between P and Q along their parallel of latitude ;

(b) distance between Q and T along their line of longitudes;

(c) average speed at which the aeroplane will fly from P to T via Q, if the journey takes 12 hours, correct to 3 significant figures. [Take the radius of the earth = 6400km ; \(\pi = 3.142\)]

View Answer & Discuss WAEC 1990
794

In a class of 40 students, 25 speak Hausa, 16 speak Igbo, 21 speak Yoruba and each of the students speak at least one of the these three languages. If 8 speak Hausa and Igbo, 11 speak Hausa and Yoruba and 6 speak Igbo and Yoruba.

(a) Draw a Venn diagram to illustrate the information, using x to represent the number of students that speak all three languages.

(b) calculate the value of x.

View Answer & Discuss WAEC 1990
795

The following is an incomplete table for the relation \(y = 2x^{2} – 5x + 1\)

x -3 -2 -1 0 1 2 3 4 5
y     8 1   -1     26

(a) Copy and complete the table.

(b) Using a scale of 2cm to 1 unit on the x- axis and 2cm to 10 units on the y- axis, draw the graph of the relation \(y = 2x^{2} – 5x + 1\) for \(-3 \leq x \leq 5\).

(c) Using the same scale and axes, draw the graph of \(y = x + 6\).

(d) Estimate from your graphs, correct to one decimal place : (i) the least value of y and the value of x for which it occurs ; (ii) the solution of the equation \(2x^{2} – 5x + 1 = x + 6\).

View Answer & Discuss WAEC 1990
796

(a) If a number is chosen at random from the integers 5 to 25 inclusive, find the probability that the number is a multiple of 5 or 3.

(b) A bag contains 10 balls that differ only in colour; 4 are blue and 6 are red. Two balls are picked one after the other, with replacement. What is the probability that:

(i) both are red? (ii) both are the same colour?

View Answer & Discuss WAEC 1990
797

(a) ABCD is a trapezium in which AB // DC, |AB| = 8cm, < ABC = 60°, |BC| = 5.5cm and |BD| = 8.3cm. Using a ruler and a pair of compasses only, construct:

(i) the trapezium ABCD ; (ii) a rectangle PQCD, where P, Q are two points AB;

(b) Measure |AB| and |QB|.

View Answer & Discuss WAEC 1990
798

The weights to the nearest kilogram, of a group of 50 students in a College of Technology are given below:

65, 70, 60, 46, 51, 55, 59, 63, 68, 53, 47, 53, 72, 53, 67, 62, 64, 70, 57, 56, 73, 56, 48, 51, 58, 63, 65, 62, 49, 64, 53, 59, 63, 50, 48, 72, 67, 56, 61, 64, 66, 52, 49, 62, 71, 58, 53, 69, 63, 59.

(a) Prepare a grouped fraquency table with class intervals 45 – 49, 50 – 54, 55 – 59 etc.

(b) Using an assumed mean of 62 or otherwise, calculate the mean and standard deviation of the grouped data, correct to one decimal place.

View Answer & Discuss WAEC 1990