Patrick purchased some supplies for his guitar students. He bought 25 guitar strings since they cost $1 more than the guitar picks. He spent a total of $40. If c is the cost of one guitar pick, find the cost of one guitar string
Let's represent the cost of one guitar string as s.
Since Patrick bought 25 guitar strings, the total cost of the guitar strings is 25s.
The cost of the guitar picks is 25s - $1 since the guitar strings cost $1 more than the guitar picks.
The total cost of the guitar picks is 25s - $1.
The total cost of the guitar strings and the guitar picks is the sum of the cost of the guitar strings and the cost of the guitar picks, which is 25s + 25s - $1 = $40.
Combining like terms, 50s - $1 = $40.
Adding $1 to both sides of the equation, 50s = $41.
Dividing both sides of the equation by 50, s = $41 / 50 = $0.82.
Therefore, the cost of one guitar string is $0.82. Answer: \boxed{0.82}.