I am trying to figure out how to do a three leveled formula.

Details...

I have three columns of information.

What I need figure out is how I can write a formula that will find a
static 'Serial Number', filter by 'Model' and then
sum the time.

example...

Serial Number = 1000

Model = AAA, BBB, CCC, AAA, AAA

Time = 10, 20, 30, 25, 5

I would find serial number 1000. Based on that, their might be
different models using the same serial number.
I want to filter by each model, in this example I have (3) AAA, (1)
BBB and (1) CCC all under the same serial number.

I will need to take all the model 'AAA' and find out their times (10
+ 25 + 5) and sum them to get the total time of 40.
I would then repeat this process for the same serial number but the
other models where BBB = 20 and CCC = 30

Does anyone know of a way to do this?