The ratio of green to yellow beads is 4:5, and there are initially 27
beads. I add some yellow beads
and the ratio is now 1:3. How
many yellow beads did I add?

Some boys and girls were asked if they had a pet. one third of the group were boys. there were 20 boys. 20% of the girls had a pet. boys with a pet : girls with a pet = 1 : 5 i need to know how many girls there are.

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi,r^3 , where r is the sphere’s radius.