Question

For a group of students of arithmetic mean of the marks in a test was 63. The brightest 30 % of them secured a mean score of 70 & the dullest 15% a mean score of 41 The mean score ofreamaining 55% is
1) 63.675
2)61.785
3) 65.18
4)66.67​

Answer 1

Answer:

1) 63.675 is he answer of that question

Answer 2

Answer: Option 3

Step-by-step explanation:

Given:

The arithmetic mean of the marks of a group of students in a test is 63. 30% of them had a mean score of 70. 15% of them had a mean score of 41.

Find:

The mean score of the remaining 55% students.

Solution:

Let us assume that there are 100 students in a group.

63 was the arithmetic mean of all students = 63 × 100= 6300

70 was the arithmetic mean of 30 students = 70 × 30= 2100

41 was the arithmetic mean of 15 students = 41 × 15= 615

Therefore, the mean score of the remaining 55 students

= 6300 - (2100+615)/55

= 6300-2715/55

= 3585/55

= 65.18

Answer:

The mean score of the remaining 55% is 65.18