There are 17 students in a certain class. On the day the test was given, vivek and abhay were absent. The other 15 students took the test, and their average was 77. The next day, vivek took the test and the average became 76. On third day, abhay also took the test and the entire class average became 77. How much should vivek have scored to take entire class average to 78? how much did abhay score?.