The answer is: A ∩ B = 7
Given: A = {4, 7, 10, 13, 17}
B = {3, 5, 7, 9}
By the symbol, ∩, we mean which terms/objects are common in the the sets given to us.
Since only, 7 is the only number which is present in both set A and set B.
Therefore, A ∩ B = 7
