If you mean test scores are worth 3 times as much as quiz scores than you simply multiply the test scores by 3 and then find the total average of tests (weighted 3 times) and quizes.
(85*3+92*3+82+75+95+84)/10 = 86.7%
Divide by 10 because each test is worth 1 quiz so it is as if there are 10 quizes