Jose bought three candy bars for a total of $18 how much did each candy bar cost

If Jose bought three Chocolate Bars for 18$ 18 divided by 3 would equal 6. Therefore each Chocolate Bar would cost 6$.

In your scenario, SQU and WRS are corresponding angles. When a line passes through two parallel lines the pair of corresponding angles are congruent. This is called the Corresponding angles theorem.  

Another example of corresponding angles in your figure would be: 
Angles SQV and QRZ
Angles WRT and UQR
Angles VQT and TRZ