Question

To pass a particular score a student has to achieve a mean of at least 50% in the ten pieces of work that form the assessment items. In the first nine of these pieces of work the student achieved a mean of 46%. What percentage mark must the student achieve in the tenth item if he is to pass the course?

Answer 1

Explanation:

the mean value is the sum of all data points divided by the number of data points.

so, in our case we have after 9 pieces of work

(p1 + p2 + p3 + p4 + p5 + p6 + p7 + p8 + p9) / 9 = 46

that means

(p1 + p2 + p3 + p4 + p5 + p6 + p7 + p8 + p9) = 46×9 =

= 414

now we need to add a p10, so that

(p1 + p2 + p3 + p4 + p5 + p6 + p7 + p8 + p9 + p10) =

= 50 × 10 = 500

only then do we get

(p1 + p2 + p3 + p4 + p5 + p6 + p7 + p8 + p9 + p10)/10 =

= 50

so,

(p1 + p2 + p3 + p4 + p5 + p6 + p7 + p8 + p9) + p10 = 500

414 + p10 = 500

p10 = 500 - 414 = 86%

the student must at least achieve 86% for the 10th piece of work.