Question

Mary, Kevin, and Ahmad served a total of 126

orders Monday at the school cafeteria. Kevin served 6
 more orders than Mary. Ahmad served 4
 times as many orders as Kevin. How many orders did they each serve?

Answer 1

Mary: 16

Kevin: 22

Ahmed: 88

Explanation:

This could be written as the following formula.

Mary + Kevin + Ahmad = 126

and we know that

Mary + 6 = Kevin

Kevin * 4 = Ahmed

so Ahmed = (Mary + 6) * 4

When filling this in you get

Mary + Mary + 6 + (Mary + 6) * 4 = 126

Mary + Mary + 6 + 4Mary + 24 = 126

6Mary + 30 = 126

6Mary = 96

Mary = 16

So Mary served 16 orders.

Using the earlier formulas you get

Kevin = Mary + 6 = 16 + 6 = 22

Ahmed = Kevin * 4 = 22 * 4 = 88.

Now we just need to double check it.

Mary + Kevin + Ahmad = 16 + 22 + 88 = 126. Which matches what it should be.