First we have to make the fractions even so there denominator have to be equal. So 15 times 2 gets 30 and 6 times 5 gets 30 too. Now multiply the numerator by the corresponding number of 25/30 and 16/30. Subtract to get 9/30 now simplify to get 3/10.
Number of tables al four restaurants have; = 4 * 30 =120 tables Two new restaurants + 4 =6 restaurants (120+15+9)= 144 tables Mean = total # of tables/ total # of restaurants; 144/6 =24 This is the mean so it decreases. I hope this helps even though you didn’t actually post the number line