John had 7 red marble and 5 blue marble in a box. Today, he put some marble in the box and the ratio is 10 red to 19 total. How many blue marbles does he put today in the box?

He amount of carbon-14 present in animal bones t years after the animal's death is given by p(t)equals=upper p 0 e superscript negative 0.00012097 tp0e−0.00012097t. how old is an ivory tusk that has lost 26% of its carbon-14?

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. x^2 - 4x - 5 = 0