Value of each coupon = $4.
Total number of lunches taken = 5.
Let us assume original price for one lunch special = p.
Total amount paid in all 5 lunches taken = $75.
We can setup an equation now,
Number of lunches( cost of each lunch - discount value of each coupon) = $75
Plugging values,
5 ( p - 4) = 75.
This is the required equation to find the original price p for one lunch special.
Distributing 5 over (p -4), we get 5*p +5*-4 = 5p -20.
5p -20 =75.
Adding 20 on both sides.
5p -20+20 =75+20
5p = 95.
Dividing both sides by 5, we get
5p/5 = 95/5
p = 19.
Therefore, the original price is $19 for one lunch special.
