Is (the fraction in the photo) rational or irrational?

Ascientist has 50 grams of a radioactive element. the amount of radioactive element remaining after t days can be determined using the equation (1) after two days the scientist receives a second shipment of 50 grams of the same element. the equation used to represent the amount of shipment 2 remaining after t days is 10) - 50 which of the following is an equivalent form of the expression for the amount remaining in shipment 2? what’s the answer?

How is this equation completed? i cannot find any examples in the book.

Divide reduce the answer to lowest term 3/7 divided 1 1/6