Question

The average weight of a certain number of students in a class is 68.5 kg. If 4 new students having weights 72.2 kg, 70.8 ...

Answer 1

Step-by-step explanation:

Given  

The average weight of a certain number of students in a class is 68.5 kg. If 4 new students having weights 72.2 kg, 70.8,70.3 kg,66.7 kg are enrolled in the class, the average weight of students increases to 300 g, Initially, how many students were there in the class?

• Let students initially in the class be s. Then sum of weights of s students in the class will be 68.5 s.
• According to question
• 68.5 x + 72.2 + 70.8 + 70.3 + 66.7 = (x + 4) (68.5 + 300 / 1000)
• 68.5 x + 280 = (x + 4) x 68.8
• 68.5 x + 280 = 68.8 x + 275.2
• 0.3 x = 4.8
• So x = 16

Answer 2

Step-by-step explanation:

you can solve it by allegation easily