Answer:
The slope of Marvin's budget constraint is the marginal rate of substitution (MRS) between the two goods, in this case, bus passes and hamburger meals. The MRS represents the rate at which Marvin is willing to give up hamburger meals for an additional bus pass, or vice versa. Therefore, without more information about Marvin's preferences and budget, it is impossible to determine the specific slope of his budget constraint and how many hamburger meals he will give up for an additional bus pass.
Uday Tahlan