In a math test, there were 20 questions of three levels: easy questions (2 points), medium questions (3 points), and hard questions (5 points). The total score of all questions was 70 points. The total score of all medium questions and the total score of all easy questions were in the ratio of 9 : 1.
Tai correctly answered all easy questions, half of the medium questions and two-third of the hard questions. How many points did he score in total? Show your work.

Ahigh-altitude spherical weather balloon expands as it rises, due to the drop in atmospheric pressure. suppose that the radius r increases at the rate of 0.02 inches per second, and that r = 36 inches at time t = 0. determine the equation that models the volume v of the balloon at time t, and find the volume when t = 360 seconds. v(t) = 4π(0.02t)2; 651.44 in3 v(t) = 4π(36 + 0.02t)2; 1,694,397.14 in3 v(t) = four pi times the product of zero point zero two and t to the third power divided by three.; 4,690.37 in3 v(t) = four pi times the quantity of thirty six plus zero point zero two t to the third power divided by three.; 337,706.83 in3