SOLVED PAPER 2020 (CDS) (II) (Elementary Mathematics)

Total Questions: 100

91. Fifteen candidates appeared in an examination. The marks of the candidates who passed in the examination are 9, 6, 7, 8, 8, 9, 6, 5, 4 and 7. What is the median of marks of all the fifteen candidates?

Correct Answer: (a) 6
Solution:

92. If the yield (in gm) of barley from 7 plots of size one square yard each, were found to be 180, 191, 175, 111, 154, 141 and 176, then what is the median of yield ?

Correct Answer: (c) 175 gm
Solution:

93. Which one of the following measures of central tendency will be used to determine the average size of the shoe sold in the shop?

Correct Answer: (a) Arithmetic mean
Solution:Average size of the shoe sold in shop by Arithmetic mean.

94. When the class intervals have equal width, the height of a rectangle in a histogram represents

Correct Answer: (d) Frequency of the class
Solution:The height of a rectangle in a histogram represents frequency of the class.

95. The ages of 7 family members are 2, 5, 12, 18, 38, 40 and 60 year respectively. After 5 year a new member aged x year is added. If the mean age of the family now goes up by 1.5 year, then what is the value of x ?

Correct Answer: (b) 2
Solution:We have,


96. The mean weight of 100 students in a class is 46 kg. The mean weight of boys is 50 kg and that of girls is 40 kg. The number of boys exceeds the number of girls by

Correct Answer: (c) 20
Solution:We have, 100 student in a class.

97. What is the algebraic sum of the deviations from the mean of a set of values 25, 65, 73, 75, 83, 76, 17, 15, 7, 14 ?

Correct Answer: (b) 0
Solution:We know that, algebraic sum of the deviation from the mean of any data is zero.

98. The mean of five observations x, x + 2, x + 4, x + 6, x + 8 is m. What is the mean of the first three observations ?

Correct Answer: (c) m - 2
Solution:Given data x, x + 2 , x + 4, x + 6, x + 8

99. What is the median of 2, 4, 6, ..., 100?

Correct Answer: (d) 51
Solution:Given, data

100. The harmonic mean and the geometric mean of two numbers are 10 and 12 respectively. What is their arithmetic mean?

Correct Answer: (d)
Solution:Given, HM = 10, GM = 12