Veto q&a 7 Month22 (1)

Q & A
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TOTAL
Plus
Weight of the new men
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Q The average of 11 observations is 60. If the Average
of first five observations is 58 and that of the last five
is 56, then what is the sixth observation?
Sum of 11 observations = 60 x 11 = 660
Sum of the first five observations = 58 x 5 = 290
Sum of the last five observations = 56 x 5 = 280
Value of sixth observations = Sum of 11
observations - (Sum of first five observations +
Sum of last five observations)
⇒ Sixth observation = 660 - (290 + 280)
= 660 - 570 = 90
Q The Average expenditure of a man for the first
five months was Rs. 120 and for the next seven
months was Rs. 130. What was his monthly average
income if he saved Rs. 290 in that year?
Total income for 12 months
= Rs (120 x 5 + 130 x 7 + 290)= 1800
1800
∴Average monthly income = = 150
12
Q Find the Average of first 25 even numbers?
Sum of the first ‘n’ even numbers = n(n+1)
= 25 (25 + 1)
= 25 x 26
= 650
Average = 650 = 26
25
Q The Average of three numbers is 15. If two numbers
are 7 and 28. The third is?
a) 14 b) 21 c) 5 d) 10
A : d) 10
Total = 15 x 3 = 45
∴7 + 28 + ? = 45
? = 10
Q A student bought 4 books for Rs. 120 from one book
shop and 6 books for Rs. 150 from another.
The average price he paid per book was?
a) 27 b) 27 1/2 c) 135 d) 138
A : a) 27
120 + 150 270
Average price = = = 27
10 10
Q The Average weight of 5 men is 67.5 kg. The average
weight is diminished by 7.5 kg, when the weight of
a boy is included, what is the weight of the boy?
a) 22.5 kg b) 30 kg c) 25 kg d) 20 kg
A : a) 22.5
Weight of the boy = 60 x 6 - 67.5 x 5 = 22.5
Q The average of three number is 28. The first number
is half of the second and the third
number is twice the second. The third number is?
a) 18 b) 24 c) 36 d) 48
Let the third number be ‘x’
x
1 x x
= x =
Second number = , First number 2 2 4
2
Sum of these numbers = (28 x 3) = 84
x x 7x
∴ x + + = 84 ⇒ = 84
2 4 4
(84×
4)
⇒ x = = 48
7
Q The mean weight of 120 students in the second year
class of a college is 56 kg. If the mean weight of
boys and that of the girls in the class are 60 kg and
50 kg respectively, then the number of boys and
girls in the class are respectively?
a) 72, 64 b) 38, 64
c) 72, 48 d) None of these
c) Let the number of boys be x. Then, number of
girls = (120 - x)
Total weight of 120 students = (56 x 120) = 6720 kg
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Q&AUbdn current affairs & gk
February 2018