The average age of 20 students is 16. 2 students of ages 17 and 13 leave the group and 2 new of ages

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14 Apr 2015 The average age of students

The average age of 20 students is 16. 2 students of ages 17 and 13 leave the group and 2 new of ages 10 and 11 join the group. New average will be.

OPtion

1) 14.25
2) 14.45
3) 14.95
4) 15
5) 15.25
6) 15.55
7) 15.75
8) 15.95
9) 16
10)None of these

Solution

20*16 = 320
Sum of the ages of leaving students = 17+13 = 30
Sum of the ages of joining students = 10+11 = 21
So new sum = 320-30+21 = 311
New avg = 311/20 = 15.55

Option 6)

Correct Option: 6 Best Solution (7)

Supriya Mondal   9 years AGO

Average age of the 20 students is 16
So, total age of the 20 students is=20*16=320
2 students of ages 17 and 13 leaves so total age of 18 students will be=320-17-13=290
Then 2 new students of ages 10 and 11 joins so new total age of 20 students will be=290+10+11=311
So, new average will be=311/20=15.55
So, option 6)15.55 is the right answer

Like? Yes (2) | No   

aman aditya   9 years AGO

16*20=320
320-17-13+10+11=311
311/20=15.55

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kranthi kanchanapally   9 years AGO

sum of age of 20 students id 20*16=320
Two people left the group of ages 17,13 and two are added with ages 10 and 11
So new age is 311
now the avg age is 311/20=15.55

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Samyak   9 years AGO

the average of 20 people is 16 . So total is 320 now substarct 17& 13 & add 10 & 11. So its 311 and divide it by 20. So ans will be 15.55

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MRITUNJAY   9 years AGO

Difference in age of replaced person=30-21=9 years
reduced average=16-9/20=15.55

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prem kishor   9 years AGO

sum of ages of 20 student =320.
after leaving two student from the group remaining sum of 18 students= 290.
after joining of two student the sum of 20 students become = 311.
then,the new average is 311/20 = 15.55

Like? Yes (1) | No   

Josepheena Joseph   9 years AGO

Sum of ages of 20 students = 20*16 = 320
Sum after leaving of 2 students and joining of 2 students
= 320 - (17+13) + (10+11) = 311
Average = 311/20 = 15.55

Like? Yes (1) | No