yes sure, i learned this before so
1. a. make a proportion here, of percentage. 
if you cross multiply and divide you get 90%.
1. b. obviously the empty seats would be 10%.
2. a. proportion again, 
cross multiply then divide you ge 15%
3. 30% in decimal form is 0.3. multiply it then to the total amount, so 0.3 x 15 = 4.5
3 + 4abs(x/2 + 3) = 11 Subtract 3
4 abs(x/2 + 3) = 11 - 3
4 abs(x/2 + 3) = 8 Divide by 4
abs(x/2 + 3) = 8/4
abs(x/2 + 3) = 2
Solution 1
x/2 + 3 = 2 Subtract 3
x/2 = 2 - 3
x/2 = - 1 Multiply by 2
x/2 *2 = - 2
x = - 2
Solution 2
x/2 + 3 = - 2
x/2 = - 2 - 3
x/2 = - 5 Multiply by 2
x = -5 * 2
x = -10
Solutions
x = - 2 <<<< answer 1
x = -10 <<<< answer 2
It would be 6.5 excuse if it was 14 it would be 7 but the other half would be 6.5
