In ravipuram up school there are 15 students in class 5 A. Teacher divided them in to 3 equal groups. Average weight of members are group1-28kg, group2- 26kg, group3- 3kg
a) how many members are there in each group?
b) Find the total weight of students in group 1 and 2?
C) one more student joined the 3rd group there is ni change in the average weight of the group. Find the weight of new student?
Answers
Answer:
a) 5 students
b) 140kg and 130kg total = 270kg
c) 3 kg
Step-by-step explanation:
Average = total weight / no. of students in grp
a)
Teacher divided them in to 3 equal groups
Total students = 15
.°. Students in each group = 15/3 = 5
b)
Group 1
No. of students = 5
Average weight = 28
.°. 28 = total weight / 5
=> 28* 5 = total weight
=> Total weight of students in gropu 1 = 140
Group 2
No. of students = 5
Average weight = 26
.°. 26 = total weight / 5
=> 26 * 5 = total weight
=> Total weight of students in gropu 2 = 130
Total weight of both group = 140 + 130 = 270
c)
No. of students = 5 + 1 ( new ) = 6
Average = 3 ( no change in average )
Total weight in 1st case where 5 students
.°. 3 = total weight / 5
=> 3*5 = total weight
=> Total weight before = 15
Total weight in 2nd case after new student added
.°. 3 = total weight / 6
=> 3*6 = total weight
=> Total weight after = 18
weight of new student = total weight after - total weight before
weight of new student = 18 - 15 = 3
Note: Even after addition of student the average weight doesnot change, the the new student weight will always be equal to the average weight