Correct option is A
Solution:
Let the missing frequency be f₁.
Arithmetic Mean = 28
Profit per Retail shop (in Rs) | Number of Retail Shops (f) | Mid Value (m) | fm |
|---|---|---|---|
0 – 10 | 12 | 5 | 60 |
10 – 20 | 18 | 15 | 270 |
20 – 30 | 27 | 25 | 675 |
30 – 40 | f₁ | 35 | 35f₁ |
40 – 50 | 17 | 45 | 765 |
50 – 60 | 6 | 55 | 330 |
Σf = 80 + f₁
Σfm = 2100 + 35f₁
Using the formula for the mean:
X̅ = Σfm / Σf
Given, X̅ = 28
=> 28 = (2100 + 35f₁) / (80 + f₁)
=> 2240 + 28f₁ = 2100 + 35f₁
=> 2240 - 2100 = 35f₁ - 28f₁
=> 140 = 7f₁
=> f₁ = 140 / 7 = 20
Hence, the missing frequency is 20.
English
100 Questions
100 Marks
90 Mins
