Five whole numbers are written in order.
7 7 x y 9
The mean and median of the five numbers are the same.
Work out the values of x and y.



Answer :

Answer:

Okay, let's approach this step by step:

In a set of numbers, the mean is the sum of all numbers divided by the count of numbers.

In a set with an odd number of numbers (like this one with 5 numbers), the median is the middle number when the numbers are arranged in order.

We are told that the mean and median are the same. This means that x must be the median, as it's the middle number in the ordered list.

Let's call the mean (and median) M. Then:

$7 + 7 + x + y + 9 = 5M$

Simplify:

$23 + x + y = 5M$

We know that x is the median, so:

$x = M$

Substitute this into the equation from step 5:

$23 + M + y = 5M$

Simplify:

$23 + y = 4M$

We are looking for whole numbers. The smallest possible value for M that makes the left side divisible by 4 is 7. Let's try that:

If $M = 7$, then $x = 7$ (because x = M)

Substituting M = 7 into the equation from step 8:

$23 + y = 4(7)$

$23 + y = 28$

$y = 5$

Check: If the numbers are 7, 7, 7, 5, 9, then:

Mean = $(7 + 7 + 7 + 5 + 9) / 5 = 35 / 5 = 7$

Median = 7

Mean = Median, so this works.

Therefore, $x = 7$ and $y = 5$.

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