The average of 4, 9, 16, 25 and x is 2x. What is the value of x? A) 4 B) 6 A) 9 C) 9 D) 12

The average of 4, 9, 16, 25 and x is 2x means that;

(4+9+16+25+x) / 5=2x

Multiply both side by 5

5 (54+x) / 5=2x (5)

54+x=10x

Subtract x to both side

54+x-x=10x-x

54=9x

Divided 9 to both side

54/9=9x/9

x=6

Check:

Substitute x with 6

(4+9+16+25+x) / 5=2x

(4+9+16+25+6) / 5=2 (6)

60/5=12

12=12; so x=6 which marks B as the correct answer. Have a nice day!