Arestaurant chain had 15,250 locations in 1975. by 2000, there were 21,655 locations. what was the percent increase in locations over the 25-year period?

It is given in the problem that in 1975, the number of restaurants chain is 15,250.
It is also given in the problem that 2000, the total number of restaurants is 21, 655. Therefore, the solution is is shown below:
% increase= ((# of restaurants is year 2000 - # of restaurants in year 1975)/number of restaurants in year 2000) * 100
% increase = (21,655-15250)/21,655 *100
% increase = 29.58%
Answer is 29.58%

C. expression because any expression or equation may contain more than one variable