hey Dear
let's solve your problem
Principal Amount = 5000
Simple Interest = 550
Time Period = 1 Year
As we know
Simple Interest = Principal × Time × Rate (in %)
550 = 5000 × 1× Rate
550 /5000 ×100 = Rate
.11×100 = Rate
11 = Rate
hence, The rate of interest is 11% Per annum
happy to help ^_^