SOLUTION: When a student weighing 45 kgs left a class, the average weight of the remaining 59 students increased by 200g. What is the average weight of the remaining 59 students

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Question 964047: When a student weighing 45 kgs left a class, the average weight of the remaining 59 students increased by 200g. What is the average weight of the remaining 59 students
Answer by LinnW(1048) About Me  (Show Source):
You can put this solution on YOUR website!
Set a = average weight of the 60 students
So 60*a is the weight of the entire class
(60a - 45kg ) = The weight of the remaining 59 students
(60a - 45kg)/59 = a + 200g
or converting to kg
(60a - 45kg)/59 = a + 0.200kg
The left hand side is the average weight of the remaining 59.
This average is 200g more than the previous average.
Now let us solve.
%2860a+-+45%29%2F59+=+a+%2B+0.200
%2860a+-+45%29%2F59+=+%28a+%2B+0.200%29%2F1
59%28a%2B0.2%29=%2860a-45%29
59a%2B11.8=60a-45
add -59a to each side
11.8=a-45
add 45 to each side
11.8=a-45
56.8=a
Since the average weight of the 59 is a + 0.200kg,
the average weight is 56.8 + 0.2 = 57kg