Multiple Criteria - Vlookup for numerical values

You don't state where your table is located, let's say for args sake the table is located in A1:D9, to retrieve column C value (0.4):

=LOOKUP(2,1/(($A$1:$A$9=30)*($B$1:$B$9=1800)),C$1:C$9)
copy this to next column so as to retrieve column D value (3)

Obviously references to 30 & 1800 can be to cell references containing those values of interest.

Going forward please also specify XL version either in your profile or in your post.