Since the average of marks scored in four tests by Jake was 75, the total marks that he scored in the four tests are 4*75 = <<4*75=300>>300
If jake scored 80 marks in the first test and 10 more in the second test, he scored 80+10= <<80+10=90>>90 marks in the second test.
The combined marks for the first and the second test is 90+80 = <<90+80=170>>170
The total marks Jake scored in the third and fourth test is 300-170= <<300-170=130>>130
Since Jake scored an equal number of marks in the third and fourth tests, he scored 130/2 =<<130/2=65>>65 marks in each of the third and fourth tests.
#### 65