Final answer:
The 5 in a 3/5 ARM represents the number of years between adjustments in the interest rate.
Step-by-step explanation:
In a 3/5 ARM, the 5 represents the number of years between adjustments in the interest rate. An adjustable-rate mortgage (ARM) has a fixed interest rate for a certain period of time, and then the rate adjusts according to market conditions. In this case, the rate remains fixed for 3 years, and then adjusts every 5 years thereafter. This allows the borrower to take advantage of potential changes in interest rates over time.