## Wednesday, 1 May 2019

### Assistant Director FIA and IB solved past paper page 8

71. $|2|-|-2|-2^2-(-2)^2=?$
(A) –8
(B) –6
(C) –4
(D) –2
72. What is the sum of the sequence: 2+4+6+ ….. +98+100 = ?
(A) 2450
(B) 2500
(C) 2550
(D) 2600
73. What is the sum of the numbers: 1, 2, 3, 4, ….. 99, 100 ?
(A) 5000
(B) 5050
(C) 5100
(D) 5150
74. In a class of 60 students the ratio of boys to girls is 3:2. How many girls are there in the class?
(A) 21
(B) 22
(C) 23
(D) 24
75. What is the volume of a right-circular cylinder in cm² having radius 2cm and height 7cm?
(A) 86 cm2
(B) 88 cm2
(C) 90 cm2
(D) 92 cm2
ANSWERS: MINISTRY OF DEFENCE TEST
71(A) Find solution below..
72(C) 73(B) 74(D) 75(B)
SOLUTIONS: MINISTRY OF DEFENCE TEST
71. (A)
72. (C) This is an arithmetic sequence with common difference of 2. The first element is 2, the last element is 100, and total elements (from 2 to 100) are 50. So, a1 = 2, an = 100, d = 2 and n = 50. So, by using the formula for the sum of n elemets of an arithmetic sequence, we have
73. (B) These are the first 100 natural numbers (n=100). So, by applying formula for the sum of the first n natural numbers, we have
74. (D)
75. (B) Here, r=2 and h=7. Hence, by using formula for finding volume of a right-circular cylinder, we have