A box of detergent costs x.
After a 40%, the box costs $6.50.
Since the final price has a 40% discount, that means the discounted price is only 60% of the original price.
60% of x equals $6.50
0.6x = 6.5
Divide both sides by 0.6
x = 10.83
Answer: The original price is $10.83