Find the square of a positive number which when decreased by 17 is equal to 60 times the reciprocal of the number.

Question: Find the square of a positive number which when decreased by 17 is equal to 60 times the reciprocal of the number.

Solution:
Let the number be x

Then, x - 17 = 60/x
⇒ x² - 17x − 60 = 0
⇒ x² - 20x + 3x − 60 = 0
⇒ (x - 20)(x + 3) = 0
∴ x = 20, - 3

The positive number = 20
Hence, the square of the positive number = 400