Given the mean of 15 of them is 18 and the mean of the rest is 13
And the total numbers are 25
So,
First, we need to find the sum of all numbers
the mean of 15 of them is 18
so, the sum of the 15 numbers are = 18 * 15 = 270
The rest of the numbers = 25 - 15 = 10
the mean of the rest is 13
so, the sum of the rest = 13 * 10 = 130
so, the sum of all numbers = 270 + 130 = 400
so, the mean of the all numbers =
So, the answer is, mean = 16
Answer:
The number of ways of selection of 3 items taking 2 at a time in addition to the possible ways in which each girl selects the same style is 9 different ways. Since the list contains 9 different ways in which each of them can select a style, the list is complete.
Step-by-step explanation:
Here we have the number of ways the available styles can be arranged between each girl is given by the number of permutation of 3 items, taking two at a time plus the number of possible selections where both of them select the same style as follows
We note that the formula for permutation is
P
=
Therefore ₃P₂ = = 6 different ways
The number of possible selections where both of them select the same style is given by
(T, T), (s, s), (L, L) = 3 different ways
Total number of ways = 6 + 3 = 9 ways
Number of different ways available in the list = 9 ways
Therefore the list is complete