Question

Greg sells gaskets. On three sales, Greg has received commissions of 385, 70, and 190, and he has one additional sale pending. If Greg is to receive an average (arithmetic mean) commission of exactly 220 on the four sales, then the fourth commission must be:

• A. $135
• B. $155
• C. $220
• D. $235
• E. $645

Hint:

To find the required value for an average, set up an equation where the sum of the values divided by the number of terms equals the given average.

Answer 1

The Correct Option is D

Step 1: Set up the equation for average commission.
The average commission is given by: \[ \frac{385 + 70 + 190 + x}{4} = 220 \] Where \( x \) is the fourth commission. Step 2: Solve for \( x \).
Multiplying both sides of the equation by 4: \[ 385 + 70 + 190 + x = 880 \] Simplifying: \[ 645 + x = 880 \] Now, solve for \( x \): \[ x = 880 - 645 = 235 \] Final Answer: \[ \boxed{235} \]