You visited us 1 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard VIII

Mathematics

Average

A group of ...

Question

A group of $10$ items has mean equal to $6$ .If the mean of $4$ of these items is $7.5$ ,the mean of the remaining items is

6.5

No worries! We‘ve got your back. Try BYJU‘S free classes today!

5.5

No worries! We‘ve got your back. Try BYJU‘S free classes today!

5

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

4.5

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is C $5$
Given, $¯ X = 6, n_{1} + n_{2} = 10; x_{1} = 7.5, n_{1} = 4, n_{2} = 6$ \
Thus using $¯ X = \frac{_{1} n_{1} +_{2} n_{2}}{n_{1} + n_{2}}$
$\Rightarrow 6 = \frac{7.5 \times 4 + 6_{2}}{10} \Rightarrow_{2} = 5$

Suggest Corrections

Similar questions

Q. A group of

10

items has arithmetic mean

6

. If the arithmetic mean of

4

of these items is

7.5

, then the mean of the remaining items is

Q. A group has

250

items with mean and standard deviation equal to

15.6

and

\sqrt{13.44}

respectively. If the second group of two samples has

100

items with mean equal to

15

and standard deviation equal to

3

, then the standard deviation of first group is

Q. The first of two groups has

100

items with mean

15

and combined group has

250

items with mean

15.6

and SD

\sqrt{13.34}

, find the SD of second group if SD of first is

3

Q. The second group of two samples has

100

items with mean

15

and S.D

= 3

.If the whole group has

250

items with mean

15.6

and S.D

= \sqrt{13.44}

, then S.D of first group is

Q. The first of two samples has

100

items with mean

15

and S.D.

3

. If the whole group has

250

items with mean

15.6

and

s . d = \sqrt{13.44}

, find the standard deviation of the second group.

Join BYJU'S Learning Program

A group of 10 items has mean equal to 6 .If the mean of 4 of these items is 7.5 ,the mean of the remaining items is

The correct option is C 5Given, ¯X=6,n1+n2=10;x1=7.5,n1=4,n2=6\Thus using ¯X=¯x1n1+¯x2n2n1+n2⇒6=7.5×4+6¯x210⇒¯x2=5

A group of $10$ items has mean equal to $6$ .If the mean of $4$ of these items is $7.5$ ,the mean of the remaining items is

The correct option is C $5$
Given, $¯ X = 6, n_{1} + n_{2} = 10; x_{1} = 7.5, n_{1} = 4, n_{2} = 6$ \
Thus using $¯ X = \frac{_{1} n_{1} +_{2} n_{2}}{n_{1} + n_{2}}$
$\Rightarrow 6 = \frac{7.5 \times 4 + 6_{2}}{10} \Rightarrow_{2} = 5$