Which of the following is an example of a combination

B and D are clearly permutation. A and B are selections but arrangement should be done for A where as C only requires selection so C is the combination.

The example which describes combination is:

Combination--

It is a method of choosing or selecting some items from a group of items.

The formula for choosing r items out of a total of n items is given by the formula:

Also, if we are selecting as well as arranging some items from a group of items then that method is known as a method of permutation.

A)

Selecting the best cake and runner up best cake from a cake decorating competition.

In this case we are choosing as well as arranging the best and runner up cake according to their ranks.

Hence, it will be a process of permutation and not combination.

B)

The number of ways 6 people can arrive at a party if no one arrive at the same time.

Again it is a problem of permutation because we have to find the number of ways the people can arrive i.e. arranging people in different orders they may arrive.

C)

Selecting 5 CD's to take with you on a trip from a collection of 30 CD's.

This is a method of combination.

Since we have to select some items from a set of items.

D)

The number of ways triplets can be born.

This is again a process of permutation.

Since there are different order they may come.

93.8

step-by-step explanation:

lets say, first number = x

second number = 3x+7

total = 49

(x)+(3x+7)= 49

4x+7 = 49

4x = 42

x = 42/4

x= 10.5

x= 10.5

3x+7 = 3(10.5)+7 = 93.8

hope this

b. an equilateral triangle inscribed in a circle

step-by-step explanation:

we are given the figure of two circles having a triangle inside.

now, we know that,

"when a figure is lying inside an another figure, then the outside figure is known as circumscribed figure and the figure lying inside is referred to as the inscribed figure".

as we see that, the circles are containing the triangle completely.

thus, the circles are the circumscribed figures and the triangle is the inscribed figure.

hence, we get, 'an equilateral triangle is inscribed in a circle'.