Question

two boys start running straight toward each other from two points that are 100m apart,one runs with a speed of 5m/s while the other moves at 7m/s.how close are they to the slower one's starting point when they reach each other

Answer 1

Assuming they travel in one-dimension we can use the x(t)= vt+1/2 at^2.
The slower boy will travel a distance X and the faster boy will travel a distance 100-X because X will be the meeting point. And there is no acceleration involved, so the equation will look like x=5t and 100-x = 7t. Solve for T on both side because they meet at the same time so both t will equal and the rest is just simple algebra