at a certain restaurant, the average ( arithmetic mean ) number of customers served for the past x days was 75. if the restaurant serves 120 customers today, raising the average to 80 customers per day, what is the value of x?	Choose one.
A) 2	B) 5	C) 7	D) 8	E) 20
<gadget id="calculator">120 - 80</gadget>
<output>40</output>

<gadget id="calculator">80 - 75</gadget>
<output>5</output>

<gadget id="calculator">40 / 5</gadget>
<output>8</output>

<gadget id="calculator">120 - 100</gadget>
<output>20</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">8 - (1/5)</gadget>
<output>39/5 = around 7.8</output>

<result>D</result>
at a certain restaurant, the average ( arithmetic mean ) number of customers served for the past x days was 75. if the restaurant serves 120 customers today, raising the average to 80 customers per day, what is the value of x?
subtract(divide(subtract(120, 80), subtract(80, 75)), divide(subtract(120, const_100), const_100))
"withoutusing the formula , we can see that today the restaurant served 40 customers above the average . the total amount above the average must equal total amount below the average . this additional 40 customers must offset the “ deficit ” below the average of 80 created on the x days the restaurant served only 75 customers per day . 40 / 5 = 8 days . choice ( a ) . withthe formula , we can set up the following : 80 = ( 75 x + 120 ) / ( x + 1 ) 80 x + 80 = 75 x + 120 5 x = 40 x = 8 answer choice ( d )"