If the mode of the following data is 140, then what is the value of x?

Class 125-130 130-135 135-140 140-145 145-150

Frequency 30 30 33 x 31

Question

Question

This question was previously asked in

RRB NTPC Graduate Level CBT-I Official Paper (Held On: 05 Jun, 2025 Shift 2)

Answer 1

Given:

Classes: 125–130(30), 130–135(30), 135–140(33), 140–145(x), 145–150(31)

Formula used:

\( \text{Mode} = l + \frac{f_1 - f_0}{2f_1 - f_0 - f_2}\times h\)

Where: Modal class = one containing the mode (140–145):

l = 140, f₁= x, f₀= 33, f₂= 31, h = 5

Calculations:

Mode = 140, so

\(140 = 140 + \frac{x-33}{2x -33 -31}\times5\)

⇒ \(\frac{x-33}{2x -64}\times5 = 0\)

⇒ 5x - 165 = 0

⇒ x = 165/5

⇒ x = 33

∴ The correct answer is option 1.

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