How to compare unequal columns and based on that pull data from an adjacent column to populate a third one

Task1 Price1  Task2 Price2
2               2      50
3               4      60
4               7      89
5
6
7

I want Price1 to be populated with开发者_StackOverflow the Price2 value if (Task1=Task2) if not then zero.Task1 is longer than Task2.

I want to do this in Excel. I don't have access to anything else. Maybe VB but don't know how to use it. I am but a lowly civil engineer don't know much about excel.

Thanks in advance for any help.

Assuming your first two columns are A and B and your price 2 is D, enter in E2

=VLOOKUP(D2,A:B,2)  

And drag that down till the end of column D.