There are 40 children in the class in which boys are four more than girls. Average weight of all the students in 42.5kg and the average weight of all the girls is 48 kg then find the average weight of all the boys
Answers
Answer:
38 kg
Step-by-step explanation:
Let the number of girls = x
=> Number of boys = x + 4
Total number of children = 40 = x + x + 4
=> 40 = 2x + 4
=> 36 = 2x
=> x = 18
Number of girls = 18
Number of boys = x + 4 = 22
Average weight of the students in the class = 42.5 kg
=> = 42.5 . . . (1)
If average weight of girls in the class is 48 kg
=> = 48
=> Total weight of 18 girls = 864 . . . (2)
Replacing value from (2) in (1)
= 42.5
=> 864 + Total weight of 22 boys = 1700
=> Total weight of 22 boys = 836
Average weight of boys =
=
= 38
Answer:
38 kg
Step-by-step explanation:
Let the number of girls = x
=> Number of boys = x + 4
Total number of children = 40 = x + x + 4
=> 40 = 2x + 4
=> 36 = 2x
=> x = 18
Number of girls = 18
Number of boys = x + 4 = 22
Average weight of the students in the class = 42.5 kg
=> \frac{Total weight of 18 girls + Total weight of 22 boys}{40}
40
Totalweightof18girls+Totalweightof22boys
= 42.5 . . . (1)
If average weight of girls in the class is 48 kg
=> \frac{Total weight of 18 girls}{18}
18
Totalweightof18girls
= 48
=> Total weight of 18 girls = 864 . . . (2)
Replacing value from (2) in (1)
\frac{864 + Total weight of 22 boys}{40}
40
864+Totalweightof22boys
= 42.5
=> 864 + Total weight of 22 boys = 1700
=> Total weight of 22 boys = 836
Average weight of boys = \frac{Total weight of 22 boys}{22}
22
Total weight of 22boys
= \frac{836}{22}
22
836
= 38