A. 18
B. 20
C. 24
D. 30
Explanation:
Average = (10 + 15 + 20 + 25 + 30)/5 = 100/5 = 20
A. 0
B. 1
C. 10
D. 19
Average of 20 numbers = 0
Sum of 20 numbers = (0 * 20) = 0
It is quite possible that 19 of these numbers may be positive and if their sum is a, then 20th number is (-a).
A. 65
B. 69
C. 72
D. None of these
Average = (76 + 65 + 82 + 67 + 85)/5 = 375/5 = 75
A. 70, 50
B. 60, 60
C. 50, 70
D. 40, 80
Let the number of boys be x.
Number of girls is 120 – x.
Total number of chocolates received by boys and girls = 2x + 3(120 – x) = 300
=> 360 – x = 300 => x = 60.
So, the number of boys or girls is 60
A. 5 : 1
B. 4 : 1
C. 3 : 2
D. 2 : 1
Let the amount lent at 7% be Rs. x
Amount lent at 10% is Rs. (6000 – x)
Total interest for one year on the two sums lent
= 7/100 x + 10/100 (6000 – x) = 600 – 3x/100
=> 600 – 3/100 x = 450 => x = 5000
Amount lent at 10% = 1000
Required ratio = 5000 : 1000 = 5 : 1
A. Rs. 21000
B. Rs. 17500
C. Rs. 19000
D. Rs. 24500
Let the cost prices of the colour television sold at 30% profit and 40% profit be Rs. x and Rs. (35000 – x) respectively.
Total selling price of televisions = x + 30/100 x + (35000 – x) + 40/100 (35000 – x)
=> 130/100 x + 140/100 (35000 – x) = 35000 + 32/100 (35000)
x = 28000
35000 – x = 7000
Difference in the cost prices of televisions = Rs. 21000
A. 21
B. 22
C. 23
D. 24
Let the initial number of members in the group be n.
Initial total weight of all the members in the group = n(48)
From the data,
48n + 78 + 93 = 51(n + 2) => 51n – 48n = 69 => n = 23
Therefore there were 23 members in the group initially.
A. 40
B. 30
C. 25
D. Data inadequate
Let the marks obtained by the student in Mathematics, Physics and Chemistry be M, P and C respectively.
Given , M + C = 60 and C – P = 20 M + C / 2 = [(M + P) + (C – P)] / 2 = (60 + 20) / 2 = 40
A. 55 years
B. 56 years
C. 58 years
D. Data inadequate
Let the present ages of A, B and C be a, b and c respectively.
Given, [(a – 5) + (b – 5)] / 2 = 40 => a + b = 90 — (1)
(b + c)/2 = 48 => b + c = 96 — (2)
From (1) and (2), we cannot find b
A. Rs.20
B. Rs.18
C. Rs.22
D. Rs.16
Average price per book = (1150 + 920) / (65 + 50) = 2070 / 115 = Rs.18