Question

5)A group of students was given a special test. The test was completed by various students in the following time (in minutes) : 18, 20, 21, 23, 25, 25, 29, 31, 31, 37
(i) Find the mean time taken by the students to complete the test?
(ii) How many students took more than the mean time to complete the test?
(iii) If the student who took 37 minutes had taken only 23 minutes to complete the test, what would have been the mean time

Answer 1

Answer:

1. Mean of time = 26 minute

2. 4 student took more time than the mean of average time.

3. New mean time = 24.4

Step-by-step explanation:

Time taken by students to complete the test = 18, 20, 21, 23, 25, 25, 29, 31, 31, 37

Total student = 10

Sum of time = 18 + 20 + 21 + 23 + 25 + 25 + 29 + 31 + 31 + 37

Sum of time = 260

1.  Mean of time = $\dfrac{total \ time}{total \ student}$

                                = $\dfrac{260}{10}$

Mean of time = 26 minute

2. 4 student took more time than the mean of average time.

3. If student take 23 minute instead of 37 minute then new sum of time is decrease by 37 - 23 minute

= 14 minute

New sum = 260 - 14

               = 244

Mean time = $\dfrac{244}{10}$

Mean time = 24.4

Answer 2

i)

$mean = \frac{18 + 20 + 21 + 23 + 25 + 25 + 29 + 31 + 31 + 37}{10}$

=260÷10

=26

ii) Mean time is 26. So, 3 students took more time than the mean (31,31,37).

iii) If the student who took 37 minutes had taken 23 minutes then the times would be:

18,20,21,23,23,25,25,26,31,31

So mean would be 246÷10=24.6

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