Students and Teachers Forum
We have, Area of ∆ABC = 27 cm2 Or, 12 ⨉ AB ⨉ BC = 27cm2 Or, 12⨉AB ⨉12cm = 27cm2 Or, AB = 4.5 cm. ∴ AB = 4.5 .....
Here, ∡ECB = 100° - 10° = 90° In right angled ∆ECB, Area = 12 ⨉EB ⨉ EC = 12 ⨉10cm ⨉ 6cm = 30 cm2 Now, area of para. ABCD = 2 ⨉ area of ∆ECB [ .....
Given, CA = b = 10 cm AB = c = 12 cm Area of ∆ABC = 60 cm2 We know, Area of ∆ABC = ½ bc SinA or, 60 = ½ ⨉ 10 ⨉ 12 SinA or, 60 .....
Here, b = 32 cm c = 41 cm ∠A = 130o . We know, Area of triangle ABC = ½ bc SinA .....
Let, AB = Original height of the pole CD = length of the broken part of the pole Let D be the point on the ground at which the top of the pole meets after broken. BC = CD Here, AD = 8 m and ∠ADC = 30o In right angled triangle ACD, tan60o = .....
Here, Join AC. Let, length of rhombus be a cm. Now, Area of ∆ACD = 12 ⨉ Area of rhombus ABCD = 12⨉18√3= 9√3 cm2 [ Diagonal bisect rhombus .....
Let, AB = height of the house CD = height of the tower AE = BD = distance between the house and the tower. Here, In right angled triangle CAE, Tan30o = 12CE/AE or,1√3 = CE60m or, CE = 20√3 m or, CE = 34.64 .....
Here, Join AC. We know, Area of ∆ACD = 12 ⨉ area of //gm ABCD [Both are standing on the same base and same parallels ] Or, 12⨉ AD⨉DC⨉sin(∡D) = 12⨉ 96√2 Or, 12⨉16 ⨉ .....
Here, AC = 8 cm and BC = 6 cm Area of ∆ABC = 12√2 cm2 Area of ∆ABC = ½ ⨉ BC ⨉ CA SinC or, 12√2 = ½ ⨉ 6 ⨉ 8 ⨉ .....
Here, b = 2.7 cm c = 4 cm ∠A = 100o . We know, Area of ▲ABC = ½ . b.c SinA .....
Here, BC = 9 cm ∡C = 60o Area of ∆ABC = 27 cm2. We know, Area of ∆ABC = ½ ⨉ BC ⨉ AC SinC or, 27 = ½ ⨉ 9 ⨉ AC Sin60o or, 27 .....
Let, AB = height of the hill = 90 m BC = distance of the object from the foot of the hill. In right angled triangle ABC, Tan45o = ABBC or, 1 = 90mBC or, BC = 90 m. So, the distance of the object from the foot of the hill .....
Here, i. CE = CD – ED = CD – AB = 25.3 – 1.3 = 24 cm ii. In right angled ∆ ACE, Tan60° = CEAE or, AE = CEtan60 = .....
We know, Area of ∆SMR = 12 ⨉ area of para. PQRS [ Both are standing on the same base and same parallels ] Or,12⨉ SM⨉ SR⨉ sin(∡MSR) = ½ ⨉ 60 Or, 12 ⨉ 5√3 ⨉ 8 ⨉ .....
We have given data, 10, 16, 22, 28, 38, 40, 46 So, n = 7. The mean of the given series is given by, .....
Marks : | 50-60 | 60-70 | 70-80 | 80-90 | 90-100 |
No. of students: | 6 | 8 | 12 | 8 | 6 |
Here,
Marks (C.I)
.....
Find the arithmetic mean from the following distribution.
Wages (Rs.) : |
0-10 | 10-20 | 20-30 | 30-40 | 40-50 |
---|---|---|---|---|---|
No. of workers: | 8 | 10 | 12 | 8 | 2 |
Here, Calculation of A.M.
Wages (Rs.) (C.I)
Height (cm): | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
---|---|---|---|---|---|
No. of plants: | 8 | 12 | 10 | 14 | 6 |
Calculation of mean:
Height (cm) (C.I)
Marks | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 |
No. of students | 4 | 5 | 10 | 8 | 7 | 6 |
C.I:
0-10
10-20
20-30
30-40
40-50
50-60
F:
8
12
?
40
12
6
Find the missing frequency.
Let the missing frequency be “a”. Then,
C.I
Rainfall (mm): | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
---|---|---|---|---|---|---|
No. of days: | 4 | 5 | 2 | 4 | 3 | 2 |
Find average rainfall.
Here,
Rainfall (mm) (C.I)
.....
Marks | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
No. of students | 4 | 6 | 15 | 20 | 5 |
Here,
Marks
.....
Marks | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
No. of students | 3 | 5 | 6 | 8 | 4 | 4 |
Here,
Marks
.....
Calculation of Median. Class interval No. of student (f) Cumulative frequency .....
Marks | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
No. of students | 5 | 6 | 8 | 10 | 7 | 4 |
Frequency Distribution Table:
We have given, N= 240, c.f = 56, f = 85 and Median class= 50 – 70. Median = .....
Marks obtained |
0-10 |
10 – 20 |
20 – 30 |
30 – 40 |
40 – 50 |
Frequency |
9 |
21 |
x |
15 |
10 |
Here, median = 24, so median class = 20 – 30. Cumulative frequency table of given data is given by:
Marks obtained |
10 – 20 |
20 – 30 |
30 – 40 |
40 – 50 |
50 – 60 |
60 – 70 |
No. of students |
4 |
5 |
10 |
8 |
7 |
6 |
Cumulative frequency table of given data is given by:
.....
The given data can be constructed in class interval of 10 as follow:
.....
Marks | 35-45 | 45-55 | 55-65 | 65-75 | 75-85 |
No. of students | 7 | 8 | 10 | 9 | 6 |
Find the median.
Calculation of Median: Marks No. of students (f) Cumulative frequency (cf) 35-45 7 7 45-55 8 15 55-65 10 25 65-75 9 34 75-85 6 40 N = .....
Here, N = 30, c.f = 8 , f = 14 and median class = 30 – 40 . The median is given by, M = .....
X |
6 – 8 |
8 – 10 |
10 – 12 |
12 – 14 |
F |
85 |
65 |
a |
100 |
Here, Third quartile (Q3) = 12, so Q3 class = 10 – 12. Cumulative frequency table of given data is given by:
.....
Here, the series given are in ascending order. No. of items = 7. Now, Median = (N+12)th term .....
Here, the given series are in ascending order. No. of terms = N = 7. Now, First quartile = (N+14)th term = (7+14)th .....
Here, the given series are in ascending order. No. of items = N = 7. Now, Third quartile = 3(N+1)4th term = 3(7+1)4th .....
Given, ∑fx=40 and N=200. We have, = ΣfxN = 40200 = 0.2. So, mean is .....
Marks | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
No. of students | 6 | 8 | 12 | 10 | 4 | 2 |
Solution:
.....
Production (m. tons): | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 |
---|---|---|---|---|---|
No. of factories: | 5 | 8 | 15 | 16 | 6 |
Calculation of Average production:
Production (m. tons) (C.I)
Solution: Frequency table
.....
Solution:
Class interval
The given data can be constructed in class interval of 10 as follow:
.....
Marks obtained |
0-10 |
0 – 20 |
0 – 30 |
0 – 40 |
0 – 50 |
Frequency |
4 |
12 |
24 |
44 |
62 |
The given data can be represented as:
Marks obtained
.....
Class interval |
0-10 |
10 – 20 |
20 – 30 |
30 – 40 |
40 – 50 |
50 – 60 |
Frequency |
12 |
18 |
27 |
k |
17 |
6 |
Calculation of mean:
.....
Given, ∑fx = 60 + 45a and , ∑f = 12 + 9a. Mean () = ? We have, Mean () = ∑fxN .....
X | 5-10 | 10-15 | 15-20 | 20-25 | 25-30 | 30-35 |
---|---|---|---|---|---|---|
F | 4 | 10 | - | 15 | 8 | 3 |
Find the missing frequency.
Here, X F Cumulative frequency (cf) 5-10 4 4 10-15 10 14 15-20 x .....
Here, N = 60, c.f = 15, f = 16 and median class = 70 – 80. The median is .....
Given, Mean= 10, ∑fx=a and N=15, We have, = ΣfxN Or, 10 = a15 Or, a = 15×10 .....
Marks | less than 10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
---|---|---|---|---|---|---|
No. of students | 4 | 10 | 14 | 15 | 5 | 2 |
Table: Marks No. of plants (f) Cumulative frequency (cf Less than .....
Class interval |
0 – 10 |
10 – 20 |
20 – 30 |
30 – 40 |
40 – 50 |
50 – 60 |
60 – 70 |
Frequency |
3 |
5 |
4 |
5 |
4 |
P |
3 |
Here, Third quartile (Q3) = 60, so Q3 class = 60 – 70 . Cumulative frequency table of given data is given .....