The average height of 42 students in a class is 4’8”. Five students of average height 4’6” moved to new section while 7 students of total height 31’10” joined the class. The average height of the students in the class is now
The average height of 42 students in a class is 4’8”. Five students of average height 4’6” moved to new section while 7 students of total height 31’10” joined the class. The average height of the students in the class is now
1). 4’6”
2). 5’
3). 4’7”
4). 4’8”
1 answers
Given,
Number of students = 42
Average height = 4’8”
? 1’ = 12’’
∴ Average height = (4 × 12) + 8 = 56’’
∴ Total height students
= Number of students × Average height
= 42 × 56 = 2352’’
Again,
Number of moved student = 5
Average height of moved students = 4’6’’ = (4 × 12) + 6 = 54’’
∴ Total height of moved students
= Number of moved students × Average height of moved students
= 5 × 54 = 270’’
Again,
Number of joined students = 7
Total height of joined students = 31’10’’ = (31 × 12) + 10 = 382’’
Now,
Number of students of the class at present = 42 – 5 + 7 = 44
Total height of these 44 students = 2352’’ – 270’’ + 382’’ = 2464’’
∴ Average height of students at present
= Total height/Number of students
= 2464’’/ 44 = 56’’
? 1’ = 12’’
∴ Average height of students at present = 56’’/12’’ = 4’8’’