The breadth of the blackboard is 30cm
The formula for calculating the perimeter of a rectangle is expressed as:
P = 2(l + w)
where:
Substituting the given parameters:
160 = 2(50 + w)
80 = 50 +w
w = 8 - 50
w = 30cm
Hence the breadth of the blackboard is 30cm
Learn more on perimeter of a rectangle here: https://brainly.com/question/19819849