Find 'p’ if the mean of the given data is 15.45.

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

answer is D.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Given that mean is 15.45.
Question Image

The expression for mean method is given as

x ¯ = ∑ f i x i ∑ f i

where

f i x i

are the product of given numbers of data in a table.
Draw a table and obtain the class marks by using the formula

lowerlimit + upperlimit 2

So,

Here, the number of total observations is

N = 30 + p

.
Applying the formula for mean method given as

x ¯ = ∑ f i x i ∑ f i

Then,

15.45 = 458 + 15 p 30 + p ⇒ 15.45 30 + p = 458 + 15 p ⇒ 463.5 + 15.45 p = 458 + 15 p ⇒ 15.45 p − 15 p = 458 − 463.5 ⇒ 0.45 p = 4.5 ⇒ p = 10

Thus, the value of

p

is 10.
Therefore, option (4) is correct.

Watch 3-min video & get full concept clarity

JEE

NEET

Foundation JEE

Foundation NEET

CBSE