13 is 26% of what number

Mrs. gehrke said cheddar weighs 16.8 pounds. he actually weighs 15.2 pounds. what is the percent error?

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

If a and −a are numbers on the number line, which expression must give the distance between them? a) 0 b) a c) |2a| d) |a|