685.The average monthly income of a person in a certain family of 5 is Rs. 1000. What will be monthly average income of person in the same family if the income of one person increased by Rs.1200 per year?
Rs.1200
Rs.1600
Rs.2000
Rs.3000
Explanation:
According to the problem ,
sum of the incomes of the 5 members in the family = Rs y
given ,
Average salary of the family = Rs 1000
⇒ y / 5 = 1000
y = 5000 ----- ( 2 )
if one member annual income increase Rupees 12000 then
increase his monthly average income = Rs 1000
now ,
sum of 5 members income now = y + 1000
= 5000 + 1000 = Rs 6000 [ from ( 2 ) ]
New average income = 6000/ 5 = 1200 [ from ( 1 ) ]
Required average salary of the family = Rs 1200
According to the problem ,
sum of the incomes of the 5 members in the family = Rs y
given ,
Average salary of the family = Rs 1000
⇒ y / 5 = 1000
y = 5000 ----- ( 2 )
if one member annual income increase Rupees 12000 then
increase his monthly average income = Rs 1000
now ,
sum of 5 members income now = y + 1000
= 5000 + 1000 = Rs 6000 [ from ( 2 ) ]
New average income = 6000/ 5 = 1200 [ from ( 1 ) ]
Required average salary of the family = Rs 1200
1649.A library has an average of 510 visitors on Sundays and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is:
250
276
280
285
Explanation:
Since the month begins with a Sunday, to there will be five Sundays in the month.
| Required average | =$ \left(\dfrac{510 \times 5 + 240 \times 25}{30} \right) $ |
| =$ \dfrac{8550}{30} $ | |
| = 285 |
1650.The average weight of 8 persons increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. What might be the weight of the new person?
76 kg
76.5 kg
85 kg
Data inadequate
Explanation:
Total weight increased = $\left(8 \times 2.5\right)$ kg = 20 kg.
Weight of new person = (65 + 20) kg = 85 kg.
1661.The average weight of 16 boys in a class is 50.25 kg and that of the remaining 8 boys is 45.15 kg. Find the average weights of all the boys in the class.
47.55 kg
48 kg
48.55 kg
49.25 kg
Explanation:
| Required average | =$ \left(\dfrac{50.25 \times 16 + 45.15 \times 8}{16 + 8} \right) $ |
| =$ \left(\dfrac{804 + 361.20}{24} \right) $ | |
| =$ \dfrac{1165.20}{24} $ | |
| = 48.55 |
1663.A pupils marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half (1/2). The number of pupils in the class is:
10
20
40
73
Explanation:
Let there be $ x $ pupils in the class.
| Total increase in marks =$ \left(x \times\dfrac{1}{2} \right) $=$ \dfrac{x}{2} $ |
| $\therefore \dfrac{x}{2} $= (83 - 63) $\Rightarrow \dfrac{x}{2} $= 20 $\Rightarrow$ $ x $= 40. |
44211.Reeya obtained 65, 67, 76, 82 and 85 out of 100 in different subjects, What will be the average.
70
75
80
85
Explanation:
$=\dfrac{65+67+76+82+85}{5}$
$=\dfrac{375}{5}$
=75
44212.Average of first five multiples of 3 is
9
11
13
15
Explanation:
$=\dfrac{3\left(1+2+3+4+5\right)}{5}$
$=\dfrac{45}{5}$
=9
44213.Average weight of 10 people increased by 1.5 kg when one person of 45 kg is replaced by a new man. Then weight of the new man is
50
55
60
65
Explanation:
Total weight increased is 1.5 * 10 = 15.
So weight of new person is 45+15 = 60
44214.Average of five numbers is 27. If one number is excluded the average becomes 25. The excluded number is
35
45
55
65
Explanation:
Number is (5*27) - (4*25) = 135-100 = 35
44215. Find the average of all numbers between 6 and 34 which are divisible by 5
15
20
25
30
Explanation:
Average=$\dfrac{10+15+20+25+30}{5}$
=$\dfrac{100}{5}$
=20
44216.A motorist travel to a place 150 km away at an avearge speed of 50 km/hr and returns ar 30 km/hr.His average speed for the whole jouney in km/hr is
36.5 km/hr
37.5 km/hr
33.5 km/hr
66.5 km/hr
Explanation:
Average speed will be
=$\dfrac{2xy}{x+y}km/hr$
=$\dfrac{2(50)(30)}{50+30}km/hr$
=37.7km/hr