I am not sure the best way to solve my problem and am hoping someone can help.

I want to be able to determine approx how long each item takes to produce.
I have types of work new, renewal and mod - and then a complexity level.
I know that it took 6980 total hrs to produce all of these items.

Assumptions that i wanted to build in:
New items take twice as long as renewals and 4 times as long as mods.
Hard items take longer then medium items and medium take longer then easy.

Totals
NEW RENEWAL MOD
EASY 53 71 87
MEDIUM 18 19 24
HARD 29 24 29


Total Hrs 6980

Is this the type of problem solver can help with, or is there aneasier way?