New learning Composite Mathematics class 5 S.K Gupta & Anubhuti Gangal Chapter 16 Average Solution
Self practice 16
1) Find the average of the following.
a) 3, 8, 10
Ans: (3+8+10)/3 = 21/3 = 7
b) 5, 0, 12, 9
Ans: (5+0+12+9)/4 = 26/4 = 6.5
c) 6, 8, 10, 12, 14, 16
Ans: (6+8+10+12+14+16)/6 = 66/6 = 11
d) 7, 5.3, 4.6, 9.1, 4
Ans: (7+5.3+4.6+9.1+4)/5 = 30/5 = 6
e) 22 min, 16 min, 43 min, 35 min, 29 min
Ans: (22+16+43+35+29)/5 = 145/5 = 29
2) Find:
a) the average of first ten even whole numbers.
Ans: The first ten even whole numbers are 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20
The average of these numbers is = (2+ 4+ 6+ 8+ 10+ 12+ 14+ 16+ 18 + 20)/ 10 = 110/10 = 11
b) the average of the first 10 counting numbers.
Ans: The first 10 counting numbers are 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10
The average of these numbers is = (1+2+3+4+5+6+7+8+9+10)/10 = 55/10 = 5.5
c) The average of the first five non-zero multiples of 5
Ans: The first five non-zero multiples of 5 are 5, 15, 25, 35 and 45
The average of these numbers is = (5+15+25+35+45)/5 = 125/5 = 25
d) The average of the first five prime numbers.
Ans: The first five prime numbers are 2, 3, 5, 7 and 11
The average of this numbers is = (2+3+5+7+11)/5 = 28/5 =5.6
3) Sunaina’s marks in monthly tests in Maths were 89 in July, 60 in August and 91 in September. What was her average score in maths for these three months?
Ans: The average score is = (89+60+91)/3 = 240/3 = 80
4) The rainfall during a period of 6 days in a city was 100mm, 74mm, 102mm, 30mm, 88mm and 56mm. What was the average daily rainfall during this period?
Ans: The Average rainfall during this period = (100+74+102+30+88+56)/6 mm = 450/6 mm = 75 mm
5) Which is more – The average of the first three even numbers (excluding zero) or the average of the first four odd numbers?
Ans: The first three even numbers are 2, 4 and 6
The average of first three even numbers is = (2+4+6)/3 = 12/3 = 4
Now, the first four odd numbers are 1, 3, 5 and 7
The average of the first four odd numbers is = (1+3+5+7)/4 = 16/4 = 4
We can see that both averages are equal.
6) Anjali saved ₹22 on Monday, ₹16.50 on Tuesday, ₹24.50 on Wednesday₹14.50 on Thursday, ₹13.50 on Friday. What was her average daily savings for these five days?
Ans: The average daily savings for these five days is ₹ (22+16.50+24.50+14.50+13.50)/5 = ₹ (91/5) = ₹ 18.2
7) The marks of 20 students of a class in an English test are given below:
50 |
50 | 37 | 49 | 27 | 16 | 13 | 39 | 40 | 45 |
50 | 70 | 19 | 42 | 48 | 47 | 29 | 25 | 18 |
20 |
a) Find the average marks of the students of the class.
Ans: The average marks of the students = (50+50+37+49+27+16+13+39+40+45+50+70+19+42+48+47+29+25+18+20)/20 = 734/20 = 36.7
b) How many students scored marks more than the average marks?
Ans: 12 students scored marks more than the average marks of 36.7.
c) How many students scored marks less than the average marks?
Ans: 8 students scored marks less than the average marks of 36.7.
8) The age, height and weight of 5 students are given in the chart below:
Name |
Age | Height | Weight |
Raman | 9 years 8 months | 1.35 m |
29.2 kg |
Arvind |
8 years 11 months | 1.34 m | 24.2 kg |
Piyush | 9 years 2 months | 1.42 m |
27.8 kg |
Siddharth |
10 years 2 months | 1.39 m | 28.8 kg |
Ashok | 9 years 10 months | 1.35 m |
22.7 kg |
Find the average
a) age
b) height and
c) Weight of the above students.
Ans:
(a) Lets convert the age of the students in months
Raman = 9 years 8 months = 116 months.
Arvind = 8 years 11 months = 107 months.
Piyush = 9 years 2 months = 110 months.
Siddharth = 10 years 2 months = 122 months.
Ashok = 9 years 10 months = 118 months.
The average age of the 5 students is = (116+107+110+122+118)/5 months = 573/5 months = 573/(12×5) years = 9.55 years
(b) The average height of the students is = (1.35+1.34+1.42+1.39+1.35)/5 m = 6.85 m
(c) The average weight of the students is = (29.2+24.2+27.8+28.8+22.7)/5 kg = 26.54 kg
See also :
New learning Composite Mathematics class 5 S.K Gupta & Anubhuti Gangal complete solution