Two riders and their distance Two riders have distance between them $118$ km and they are moving   towards each other to meet . B starts an hour later by A. A travels $7$km in hour while B travels $16$km every three hours. How many kilometers(km) will A have already traveled, once they meet each other?
Could anyone help me with this puzzle?

The speed of B is $16/3=5\frac{1}{3}$ km per hour. When he starts, A has already driven 7 km. You can therefore model the driving of the 2 by the equation 
$7x+7=5\frac{1}{3}x$
do you understand why this is an equation?
Where the left hand side represents A, the RHS represents B, and x is the amount of time (in hours).
Can you do the rest? 
