4. The mean of 12 numbers is 5.5. Eleven

of the numbers are 5, 6,5,3,4,5,7,6,9,

7 and 5. Find

a) the twelfth number.

b) the mode of the twelve numbers.

c) the sum of the mode and the mean.

a) 4

b) 5

c) 9

Step-by-step explanation:

a) let the 12th number b x

Mean = sum/n

5.5 = (5+6+5+3+4+5+7+6+9+7+5+x) / 12

5.5*12 = 62+x

66 = 62+x

x = 4

b) set is: 3,4,4,5,5,5,5,6,6,7,7,9

Mode is 5 (most frequent)

c) mode+mean = 5+4 = 9

A) 4

B) Mode is 5

C) 10.5

Step-by-step explanation:

A) 62+x/12

(62 + x) : 12 = 5.5 * 12

62 + x = 66

* = 66-62

*=4

B) mode is the highest occuring no which is 5

C) mean has been given as 5.5; mean plus mode = 10.5