Step-by-step explanation:
the mean value is the sum of all data points divided by the number of data points.
first we have 7 tests and their mean value :
(t1 + t2 + t3 + t4 + t5 + t6 + t7) / 7 = 54
that means
(t1 + t2 + t3 + t4 + t5 + t6 + t7) = 54 × 7 = 378
in order for the mean value to be at least 60% after 8 tests, we need to add a t8, so that
(t1 + t2 + t3 + t4 + t5 + t6 + t7 + t8) = 60 × 8 = 480
because only then we have
(t1 + t2 + t3 + t4 + t5 + t6 + t7 + t8) / 8 = 60
and the student passes.
so,
(t1 + t2 + t3 + t4 + t5 + t6 + t7) + t8 = 480
378 + t8 = 480
t8 = 480 - 378 = 102%
the student would have to achieve 102% on the 8th test.
which would be normally impossible, but maybe the tests involve some bonus points.
