Answer:
30
Explanation:
Since we have five numbers and their mean is 16 as we all know that
mean = summation of total numbers / summation of total number of terms
Mean = 16 for 5 numbers
sum = 16 x 5 = 80( sum of the five terms)
when two extra numbers are added, it then becomes 7 numbers . since the numbers are unknown we then represent each numbers with the X and Y
New sum = 80 + x + y
new number of terms = 7
new mean = 20
20 = 80 + x + y
7 we cross multiply to get the unknown values
20 x 7 = 80 + x + y , 140 = 80 + x + y
we use y as subject of the formula to get x
140 - 80 + x = y
60 + x = y, y = 60 + x
we input y = 60 + x into the equation (140= 80 + x + y) to get x
140 = 80 + x + 60 + x , 140 = 80 + 60 + x + x
140 = 140 + 2x , 140 -140 = 2x
0 = 2x , divide both sides by 2 to get x
x = 0
we then input x = 0 into the equation to get y
140 - 80 + x = y
140 - 80 + 0 = y , 60 + 0 = y
y = 60
To find the mean of the two extra numbers, we then use the above formula for finding mean.
60 + 0 / 2 = 60 / 2 =30
mean = 30.