Veto q&a 7 Month22 (1)

60x + 50 (120 - x) = 6720
⇒10 x = 720
x = 72
Number of boys = 72
Number of Girls = (120 - x) = 120 - 72 = 48
Q The average weight of 20 persons living in building A
of Indraprastha Colony is 60 kg. In the same colony
the average weight of 24 persons living in building
B is 58 kg. Find the combined average weight of
persons living in that colony?
Average
20 × 60 + 24 × 58 1200 + 1392
= = = 58.9kg
20 + 24 44
Q Rita’s marks in four tests are 82, 80, 76 and 70.
How many marks must she get on the fifth test to
raise her average to 80?
a) 86 b) 88 c) 92 d) 96
c) Total mark of a subject
= 76 + 82 + 80 + 70 = 308
80 x 5 = 400
Fifth test mark is = 400 - 308 = 92
Q The average age of a set of 30 persons is 35. The
average of 20 person of the set is 20. What will be
the average of the remaining set?
a) 15 b) 45 c) 65 d) 35
c) The required Average
30 × 35 − 20 × 20
=
10
650
= = 65
10
Q The average of 9 numbers is 50. The average of first
four is 52 and the average of last four is 49. What is
the fifth number?
a) 46 b) 40 c) 44 d) 48
Total of 9 numbers = 9 x 50 = 450
Total of first four numbers = 4 x 52 = 208
Total of last four numbers = 4 x 49 = 196
Fifth number = 450 - (208 + 196) = 46
Q The average weight of 8 men is increased by 1.5 kg
when one of the men who weight 65 kg is replaced
by a new man. The weight of the new man is?
@hang out
a) 70 kg b) 74 kg c) 76 kg d) 77 kg
d) Increased weight = (1.5 x 8) kg = 12 kg
Weight of the new man = (65 + 12) kg = 77 kg
Q There were 35 students in a hostel. If the number of
students be increased by 7, the expenditure on food
increases by Rs. 42 per day. While the average
expenditure of students is reduced by Rs.1. What
was the initial expenditure on food per day?
a) 432 b) 442 c) 420 d) 400
Let the original expenditure be Rs. x,
Then,
x ( x + 42)
− = 1⇒6x
− 5( x + 42) = 210
35 42
⇒ x = 420
Original expenditure = Rs. 420
Q Ten years ago the average age of a family of 4
members was 24 years. Two children having been
born, the average age of the family is same today.
What is the present age of the youngest child if they
differ in age by 2 years?
a) 1 years b) 2 years
c) 3 years d) 5 years
c) Let the age of youngest child be ‘x’ years. Then,
age of the other child = (x + 2) years
Average age of 6 members today = 24 years
Sum of the ages of 6 members today = (24 x 6)
years = 144 years
(24 x 4) + (10 x 4) + x + (x + 2) = 144
2x = 6
x = 3
Q The average age of a husband and a wife was 23
years when they were married 5 years ago. The
average age of the husband, the wife and a child
who was born during the interval, is 20 years now.
How old is the child now?
a) Less than 1 year b) 1 year
c) 3 years d) 4 years
d) Total age of husband and wife now
= [(23x2) + (5x2)] years = 60 years
∴Age of the child = (60 - 56) years = 4 years
Q&A Bonus
tIcf BtcmKy kÀÆIemime þ apf¦p¯pImhv
33