Auto inserting a formula when using Data Validation list

Hi,
I am hoping someone can help.

I am working on a spreadsheet where I would like to be able to make a selection from a drop down list and auto insert a formula relating to the selection made.

Working on the example attached I would like to be able make a selection from the drop down list under "TYPE", which will auto fill "RATE" and auto insert a formula into the "COST" boxes (Data on RATES tab).
Depending on the selection under "TYPE" would depend on the formula inserted under "COST".

Formula to be inserted:
For selections 1M, 2M and OUT I would like to formula to be RATE ÷ 60 x TIME.
For selections COOK and MAT I would like the formula to be RATE x TIME.

I would like the formula row to auto change to the row that it is being inserted on, so it is unique to the figure put in TIME on that row.

Currently I have it inserting the formula as text not a formula and cannot get it to change to suit the row it is on.

I hope that makes sense and what I am asking is possible.

Thanks