Answer :
mean = total score : frequency
mean x frequency = total score
so
83 = total score : 6
83 × 6 = total score
498 = total score
so the sum of the 6 test scores is 498
mean x frequency = total score
so
83 = total score : 6
83 × 6 = total score
498 = total score
so the sum of the 6 test scores is 498