Question

If mean of 15, 8, 12, a, b, c, 20, 6, 17 and 9 is 12 then find the mean of a, b and c.​

Answer 1

Answer:  10

Step-by-step explanation:

Mean = Total sum/number of elements hence,

12 = (15+8+12+a+b+c+20+6+17)/9

12*9 = 78 + a+b+c

108=78+a+b+c

a+b+c = 108-78 = 30

now, a+b+c=30

mean of a,b,c = (a+b+c)/3 (see above formula)

mean= 30/3 =10

Answer 2

Step-by-step explanation:

Mean × 10 (10 terms)= 15+8+12+20+6+17+9+a+b+c

12 × 10 =87+a+b+c

120 - 87 = a+b+c

Mean of a,b,c = (a+b+c)/3

Mean of a,b,c = (120-87)/3

Mean of a,b,c = 33/3

Mean of a,b,c = 11