Ray is 23 years older than his sister carol. in 20 years he will be twice as old as carol. how old is each of them now

In the xy-plane, if the parabola with equation passes through the point (-1, -1), which of the following must be true?

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?

Using the figure below, select the two pairs of alternate interior angles. a: point 1 and point 4 b : point 2 and point 3 c: point 6 and point 6d: point 5 and point 7