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!

Your post does not comply with Rule 1 of our Forum RULES. Your post title should accurately and concisely describe your problem, not your anticipated solution.

Use terms appropriate to a Google search. Poor thread titles, like Please Help, Urgent, Need Help, Formula Problem, Code Problem, and Need Advice will be addressed according to the OP's experience in the forum: If you have less than 10 posts, expect (and respond to) a request to change your thread title. If you have 10 or more posts, expect your post to be locked, so you can start a new thread with an appropriate title.

To change a Title go to your first post, click EDIT then Go Advanced and change your title, if 2 days have passed ask a moderator to do it for you.

(This thread should receive no further responses until this moderation request is fulfilled, as per Forum Rule 7)

Perhaps post a sample sheet after that