If y varies directly as x , and y is 180 when x is n and y is n when x is 5 , what is the value of n ?

In a direct variation, y = kx for some constant k. The two conditions give 180 = kn and n = 5k, so k = n/5 and n² = 900. Thus n = 30 or −30; among the choices, 30 is listed, so the answer is D, 30. Without a restriction that n is positive, the information also permits −30.

AI-written and checked against the verified answer.