[Question]: A plumber is trying to decide which of three different jobs he should take to make the most money. The first job involves fixing three toilets and three sinks at an apartment complex. The second involves two toilets and five sinks at a different apartment complex. The third involves fixing one toilet, two showers and three sinks at a third apartment complex. If the plumber charges $30 to fix a sink, $40 to fix a shower and $50 to fix a toilet, what is the most money the plumber can earn if he can only choose one of these three jobs?
[Answer]: If the plumber chooses the first job, he would earn 3 * 50 + 3 * 30 = $240. If he chooses the second, he'd earn 2 * 50 + 5 * 30 = $250. If he chooses the third, he'd earn 50 + 2 * 40 + 3 * 30 = $220. Therefore, the most money he can earn from one of these jobs is $250.
So the answer is 250.

[Question]: A bottle can hold 2 cups of water. How many cups of water are needed to fill up 10 whole bottles and 5 half-capacity bottles?
[Answer]: For 10 whole bottles, you will need 10 * 2 = 20 cups of water. With 5 half - capacity bottles, it requires 5 * 1 = 5 cups of water. In total, you need to have 25 + 5 = 30 cups of water to fill them all.
So the answer is 30.

[Question]: There are 30 fish in the tank. One third of them are blue, and half of the blue fish have spots. How many fish in the tank are blue, spotted fish?
[Answer]:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
There are 30 / 3 = 10 blue fish. There are 10 / 2 = 5 blue spotted fish.
So the answer is 5.