Final answer:
To find the initial number of donuts Bob bought, set up a system of equations using the given information and solve for the value of x.
Step-by-step explanation:
To find the initial number of donuts Bob bought, we can set up a system of equations using the given information. Let's assume Bob bought x donuts initially. After 15 minutes, he had 36 donuts, so the equation is: x - 15 = 36. After 23 minutes, he had 12 donuts, so the equation is: x - 23 = 12. We can solve this system of equations to find the value of x. Subtracting 15 from both sides of the first equation, we get x = 36 + 15 = 51. Subtracting 23 from both sides of the second equation, we get x = 12 + 23 = 35. Since these two values for x don't match, there must be an error in the given information or a typo. Please double-check the question or provide more information for further assistance.