Forumla to search row then down column based on specific criteria

I have a large table with information similar to the below set up. I need a formula that will first look up the tank from the tank I specify. In this example, I want the formula to look up in row A1: D1 tank 30, then look down that column and find the BBLs specified, in this example 5000, then return what is in column A which would be 80

_____A______B______C______D
1___________20_____30_____40
2____60____1000___4000___2000
3____80____2000___5000___4000
4____90____3000___6000___6000


Tank 30
BBLS 5000

Thank you!