The average of 5, 10, 15, and z is 20. What is z?

50

Step-by-step explanation:

Step 1:

5 + 10 + 15 + z / 4 = 20        Equation

Step 2:

30 + z / 4 = 20         Combine Like Terms

Step 3:

30 + z  = 20 × 4    Multiply 4 on both sides

Step 4:

z = 80 - 30      Subtract 30 on both sides

z = 50

Hope This Helps :)