Answer:
Mode = l + [(f₁ - f₀)/(2f₁ - f₀ - f₂)]h
Where, l is the lower limit of the modal class
f₁ is the frequency of the modal class
f₀ is the frequency preceding the modal class
f₂ is the frequency succeeding the modal class
h is the class size
From the table,
Maximum frequency = 41
This frequency lies in the class 10000 - 15000
l = 10000
h = 5000
f₁ = 41
f₀ = 26
f₂ = 16
Now, f₁ - f₀ = 41 - 26 = 15
2f₁ - f₀ - f₂ = 2(41) - 26 - 16
= 82 - 42
= 40
[(f₁ - f₀)/(2f₁ - f₀ - f₂)] = 15/40
= 3/8
Now, mode = 10000 + (3/8)(5000)
= 10000 + (15000/8)
= 10000 + 1875
= 11875
Therefore, the modal income is 11875.