The average (arithmetic mean) of 5, 10, 15 and x is 20. What is the value of x?
The average (arithmetic mean) of 5, 10, 15 and x is 20. What is the value of x?
Explanation
That makes it 4 x 20 to get the total sum which is 80
80=5+10+15+x
80–30=x
50=x