If 45 cookies will serve 15 students, how many collies are needed for 30 students?

A50% increase followed by 33 1/2% decrease

Asquare and an equilateral triangle have the same perimeter. each side the triangle is 4 inches longer than each side of the square. what is the perimeter of the square

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.