The average of 5 numbers is 4 .
a sixth number is added to the set which increases the mean to 7 .what is the 6th number

The sixth number is 22. Surprisingly, the exact values of the first five numbers do not matter. See the explanation.

Step-by-step explanation:

Let the sixth number be . The average of numbers is equal to the sum of these number divided by . That is:

.

Working backwards (multiply both sides by the denominator, ) to find a formula for the sum of the numbers:

.

Apply this formula to find the sum of the first five numbers:

.

If represents the value of the sixth number, the sum of the first six numbers will be equal to:

.

The average of the first six number will thus be equal to:

.

However, the question states that the average of the first six numbers is equal to . In other words,

.

Multiply both sides by the denominator, :

.

.

In other words, the sixth number is .

i think it would be 43 movies that would have to be watched.

step-by-step explanation:

think about it. for the second plan, every month is 8 dollars. 8 x 12= 96. so thats the number for the second plan. now for the first plan, its annual meaning you have to pay 10 dollars every year. so now you have to get an equivalent amount of 86 since 96-10=86. 86 divided by 2 since every movie costs 2$ then you would have to watch 43 movies a year to get the same as the second plan. i really hoped this . have a wonderful day as well!