actually just think of it like this, the 120m/12ms^-1 means he takes a total of 10 seconds to travel. That 10 seconds is the same time it takes for the the 13ms^-1. Thus 13m*10sec=130metres.
actually just think of it like this, the 120m/12ms^-1 means he takes a total of 10 seconds to travel. That 10 seconds is the same time it takes for the the 13ms^-1. Thus 13m*10sec=130metres.