Percentage of grade

Question

If I score a 64 and a 79 on two tests and I have two more tests to take and I have to get an 80% overall in the class what’s the lowest score I need on the final two tests

Answer 1

Let x = score on each of the remaining two tests

(64 + 79 + x + x)/4 = 80

143 + 2x = 320

2x = 177

x = 88.5%