Question

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?

Answer 1

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