Using a Dummy Variable

Hello, I have a dummy variable cell that is either 1 or 0

I have another row of values. How can I incorporate this dummy variable cell in the function of this row of values such that their values are increased by 30% when the dummy cell is 1, or stay as is if the dummy cell is 0.

i.e

1. row is 1 , 10, 100, 1000.
2. change dummy variable cell to 1
3. row becomes 1.3, 13, 130, 1300 etc

I hope the above makes sense. I want to do this without using any advance tools.

Any help much appreciated in advance! This is for an assignment that is due shortly!