I have 3 columns of data, the first designates the currency of sales, the
second identifies the type of value input and the third is the value. I would
like add the total of only the "sales" in column (C) that have a cell 2
columns to the left (A - Currency) that contains a specific value (USD).

A B C
1 Currency Type Value
2 USD Sales $374.40
3 Freight $0.00
4 Freight % 0.00%
5
6 USD Sales $0.00
7 Freight $0.00
8 Freight % 0.00%
9
10 CAD Sales $2,635.14
11 Freight $63.13
12 Freight % 2.40%
13
14 USD Sales $0.00
15 Freight $0.00
16 Freight % 0.00%
17
18 CAD Sales $31,084.11
19 Freight $2,366.53
20 Freight % 7.61%


The total in this case would be $374.40