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) 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

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

option 1 is correct.

step-by-step explanation:

y varies inversely with x and constant of variation is 4

the equation will be:

y = k/x

where k =4 so,

y = 4/x

if we put values of x of option 1 in the above equation and find values of y

y = 4/-2 => y =-2

y = 4/-1 => y = -4

y = 4/1 => y = 4

y = 4/2 => y =2

so, all the values of x and y are correct.

if we put values of x given in other options and find value of y we cannot find whole table satisfying the equation.

hence option 1 is correct.

where's the diagrams?