KCSE MATHEMATICS QUESTIONS AND SOLUTIONS ~ Topically Analyzed
Comprehensive Answers and Marking Schemes KNEC Certified
Form 4 Mathematics
A building contractor has two lorries, P and Q, used to transport at least 42 tonnes of sand to a building site. Lorry P carries 4 tonnes of sand per trip while lorry Q
carries 6 tonnes of sand per trip. Lorry P uses 2 litres of fuel per trip while lorry Q uses 4 litres of fuel per trip. The two lorries are to use less than 32 litres of fuel. The number of trips made by lorry P should be less than 3 times the number of trips made by lorry Q. Lorry P should make more than 4 trips. (a) Taking x to represent the number of trips made by lorry P and y to represent the number of trips made by lorry Q, write the inequalities that represent the above information. (b) On the grid provided, draw the inequalities and shade the unwanted regions. (c) Use the graph drawn in (b) above to determine the number of trips made by lorry P and by lorry Q to deliver the greatest amount of sand.
0 Comments
Form 3 Mathematics
The cost C, of producing n items varies partly as n and partly as the inverse of n. To produce two items it costs Ksh 135 and to produce three items it costs Ksh 140. Find:
(a) the constants of proportionality and hence write the equation connecting C and n; (b) the cost of producing 10 items; (c) the number of items produced at a cost of Ksh 756. Form 4 MathematicsForm 3 Mathematics
The table below shows values of x and some values of y for the curve y = x^{3} + 2x^{2}  3x – 4 f o r  3 ≤ x ≤ 2.
(a) Complete the table by filling in the missing values of y, correct to 1 decimal place.
(b) On the grid provided, draw the graph of y = x^{3}+ 2x^{2}  3x  4. Use the scale: 1 cm represents 0.5 units on x axis. 1 cm represents 1 unit on yaxis. (c) Use the graph to: (i) solve the equation x^{3} + 2x^{2}  3x  4 = 0; (ii) estimate the coordinates of the turning points of the curve. Form 3 Mathematics
A parent has two children whose age difference is 5 years. Twice the sum of the ages of the two children is equal to the age of the parent.
(a) Taking x to be the age of the elder child, write an expression for: (i) the age of the younger child; (ii) the age of the parent. (b) In twenty years time, the product of the children's ages will be 15 times the age of their parent. (i) Form an equation in x and hence determine the present possible ages of the elder child. (ii) Find the present possible ages of the parent. (iii) Determine the possible ages of the younger child in 20 years time. Form 4 MathematicsForm 3 Mathematics
The first, fifth and seventh terms of an Arithmetic Progression (AP) correspond to the first three consecutive terms of a decreasing Geometric Progression (G.P).
The first term of each progression is 64, the common difference of the AP is d and the common ratio of the G.P is r. (a) (i) Write two equations involving d and r. (ii) Find the values of d and r. (b) Find the sum of the first 10 terms of: (i) The Arithmetic Progression (A.P); (ii) The Geometric Progression (G.P). Form 1 Mathematics
The cash price of a laptop was Ksh 60 000. On hire purchase terms, a deposit of Ksh 7 500 was paid followed by 11 monthly installments of Ksh 6 000 each.
(a) Calculate: (i) the cost of a laptop on hire purchase terms; (ii) the percentage increase of hire purchase price compared to the cash price. (b) An institution was offered a 5% discount when purchasing 25 such laptops on cash terms. Calculate the amount of money paid by the institution. (c) Two other institutions, X and Y, bought 25 such laptops each. Institutions X bought the laptops on hire purchase terms. Institution Y bought the laptops on cash terms with no discount by securing a loan from a bank. The bank charged 12% p.a. compound interest for two years. Calculate how much more money institution Y paid than institution X. Form 4 MathematicsForm 3 Mathematics
The equation of a circle centre (a, b) is x^{2} – y^{2} – 6x  10y + 30 = 0. Find the values of a and b.
Form 4 Mathematics
A point M (60°N, 18°E) is on the surface of the earth. Another point N is situated at a distance of 630 nautical miles east of M.
Find: (a) the longitude difference between M and N; (b) The position of N. Form 2 Mathematics
Vector OP= 6i  j and OQ = 2i  5j. A point N divides PQ internally in the ratio 3:1.
Find PN in terms of i and j. Form 4 MathematicsForm 1 MathematicsForm 3 Mathematics
The radius of a spherical ball is measured as 7 cm, correct to the nearest centimeter. Determine, to 2 decimal places, the percentage error in calculating
the surface area of the ball. Form 2 Mathematics
The vertices of a triangle are A(1,2), B(3,5) and C(4,1). The coordinates of C' the image of C under a translation vector T, are (62).
(a) Determine the translation vector T. (b) Find the coordinates of A' and B' under translation vector T. Form 3 Mathematics
The ages in years of five boys are 7, 8, 9, 10 and 11 while those of five girls are 4, 5, 6, 7 and 8. A boy and a girl are picked at random and the sum of their ages is recorded.
(a) Draw a probability space to show all the possible outcomes. (b) Find the probability that the sum of their ages is at least 17 years. Form 2 MathematicsForm 2 Mathematics
(a) Solve the inequalities 2x — 5 >  11 and 3 + 2x ≤ 13, giving the answer as a combined inequality.
(b) List the integral values of x that satisfy the combined inequality in (a) above. Form 1 Mathematics
Three grades A, B, and C of rice were mixed in the ratio 3:4:5. The cost per kg of each of the grades A, B and C were Ksh 120, Ksh 90 and Ksh 60 respectively.
Calculate: (a) The cost of one kg of the mixture; (b) The selling price of 5 kg of the mixture given that the mixture was sold at 8% profit, Form 2 Mathematics
The frequency table below shows the daily wages paid to casual workers by a certain company.
(a) Draw a histogram to represent the above information.
(b) (i) State the class in which the median wage lies. (ii) Draw a vertical line, in the histogram, showing where the median wage lies. (c) Using the histogram, determine the number of workers who earn sh 450 or less per day. Form 3 Mathematics 
Categories
All
