Are you smarter than a fifth grader- Part 5

Algebra Level 4

In a 1 km race, A wins B by 40 meters and A wins C by 70 meters (same race). Assuming that they run at constant speed, the distance by which B wins C in the race can be expressed in the form $\frac{x}{y}$ , where $x$ and $y$ are coprime positive integers. Find $x \times y$ .