Answer: 11 weeks
Explanation:
Hi, to answer this question we have to place the total hire charge value (743) in the equation give, and solve for x (number of weeks) 
Total hire charge in ( £) = 63x+ 50 
Replacing with the hire charge given: 
743 = 63x+50 
Solving for x: 
743-50= 63x 
693=63x 
693/63=x 
x =11 weeks 
Feel free to ask for more if needed or if you did not understand something.