Question

If the mean of x + 1, x + 12, 2x + 3, and 3x + 5 is 21 , then the value of x is ?

• A. 12
• B. 10
• C. 8
• D. 9

Answer 1

Answer:

D. 9

Mean = sum of obsevations / number of obsevations 21 = {x+1 + x + 12 + 2x + 3 + 3x + 5}/4 21 = {7x + 21}/4 84 = 7x + 21 7x = 84 - 21 = 63 x = 63/7 = 9