I need hellp please help meee

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

The volume of the sun is approximately 1 × 10^18 cu km, while the volume of jupiter is approximately 1 × 10^15 cu km. which of the following is true? a. the volume of jupiter is approximately one thousand times the volume of the sun. b. the volume of jupiter is approximately one hundred times the volume of the sun. c. the volume of the sun is approximately one thousand times the volume of jupiter. d. the volume of the sun is approximately one hundred times the volume of jupiter.

Petes dog weighed 30 pounds it then lost 16% of it's weight how much did pete lose