Sita needs a perfect score of 100 for math test in this year so as to improve on her average score from 84 to 86. How many maths tests were there altogether in this year?
number of tests before the last one ---> x
total marks at that point = 84x
then (84x + 100)/(x+1) = 86
86x + 86 = 84x + 100
2x = 14
x = 7
So there were 8 tests, including his perfect test at the end.