How many positive integers less that 50 have irrational square roots?

It is easier to calculate how many integers are perfect squares and then subtract that number from 50.

1² = 1

2² = 4

3² = 9

4² = 16

5² = 25

6² = 36

7² = 49

There are 7 numbers that have perfect squares, so there are 50 - 7 = 43 that have irrational square roots.

Answer: 43