Devon has 100 dimes and quarters. If the total value of what he has is $21.40, how many of each coin type does he have?

What number should be added to both sides of the equation to complete this square? x^2-10x=7

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.

Write a function for a rotation 90 degrees counter clockwise about the origin, point 0