Combined Defence Services
CDS Elementary Mathematics Solved Exam Paper (I) : 2007
1. If the mean of the variable X is M, what is the mean of variable Y = (X – 4)/ 5?
(a) (M – 4)/ 5
(c) M – 5
(d) 5M – 4
2. A batsman scores 80 runs in his sixth innings and thus increases his average by 5. What is his average after six innings?
3.What type of classification is needed to enumerate the female population of India?
4 .What is the geometrical mean of the variate which takes values 210, 201, 102, 20, 12, 10, 2, 1 and 0?
5. The vertical height of a right circular cone is twice its diameter and its volume is 36 cm3. What is its vertical height?
(a) 4 cm
(b) 8 cm
(c) 12 cm
(d) 16 cm
6. A wax cube of edge 6 cm is melted and formed into three smaller cubes. If the edges of two smaller cubes are 3 cm and 4 cm, what is the edge of the third smaller cube?
(a) 5 cm
(b) 4.5 cm
(c) 4 cm
(d) 3.5 cm
7. A right circular cylinder and a right circular cone have equal bases and equal volumes. But the lateral surface area of the right circular cone is 15/ 8 times the lateral surface area of the right circularcylinder. What is the ratio of radius to height of the cylinder?
(a) 3 : 4
(b) 9 : 4
(c) 15 : 8
(d) 8 : 15
8.Water i s di st r ibuted to a town 50000 inhabitants from a rectangular reservoir consisting of 3 equal compartments. Each compartment has length and breadth 200 m, 100 m respectively and 12 m depth of water in the beginning. The allowance is 20 litres per head per day. For how many days will the supply of water hold out?
(a) 240 days
(b) 720 days
(c) 800 days
(d) 900 days
9. A swimming pool is 24 m long and 15 m broad. When x number of men dive into the pool, the height of the water rises by 1 cm. If the average amount of water displaced by one man is 0.1 m3, then what is the value of x?
10. The diameter of a bus wheel is 140 cm. The speed of the bus is 66 km per hour. What is the number of revolutions of the wheel per minute?