To represent Wang Hao's budget for dairy products in terms of goat milk (G) and cow's milk (C), we can set up the following inequality.
The cost for goat milk is $2.40 per liter, so if Wang Hao buys \(G\) liters of goat milk, the total cost for goat milk will be \(2.40G\).
The cost for cow's milk is $1.20 per liter, so if he buys \(C\) liters of cow's milk, the total cost for cow's milk will be \(1.20C\).
Wang Hao wants to spend at most $15, which means the total cost of both types of milk combined must be less than or equal to $15. Therefore, we can write the inequality as:
\[ 2.40G + 1.20C \leq 15 \]
This inequality represents the number of liters of goat milk \(G\) and cow's milk \(C\) Wang Hao can buy without exceeding his budget of $15.