Puzzle | Missing One Rupee I came across the following riddle.

A group of $30$ Indian merchants go to a hotel and stay there for a night. The hotel owner provides for their lunch and breakfast. He serves dinner at the rate of $2$ plates/$\large{₹}$ and breakfast at the rate $3$ plates/$\large{₹}$. When the merchants check out in the morning they are given the bill of $\large{₹}25$ for their food. As per the owner $30$ dinners at the rate of $2$ plates/$\large{₹}$ equals to $\large{₹}15$, and $30$ breakfast at the rate of $3$ plates/$\large{₹}$ equals to $\large{₹}10$, and hence $\large{₹}25$$(10+15)$.
However the merchants give the owner $\large{₹}$$24$ claiming that dinner and breakfast together costed $5$ plates for $\large{₹}$$2$. Therefore, $60$ plates ($30$ of night and $30$ of morning) costs $\frac{2}{5}\times 60 = \large{₹}$ $24$.
Whom do you favor, merchants or the owner, and why?

I am unable to decide who is correct as mathematically they both appear correct to me. Is there a way to find out as to which method is wrong and which is correct one?

The financier in me says that 3 breakfasts at for 1 rupee at 67 rupee / dollar, this hotelier cannot afford to give away food so cheaply.  And these merchants should just pay the additional rupee.
Nonetheless... A plate of breakfast is not a plate of lunch.  When the merchants say say "5 plates for 2 rupees."  That is 2 lunches and 3 breakfasts.  Yet, they are not buying 3 breakfasts for every 2 lunches, they are buying an equal number of each, and the lunches cost more.
