The average weight of three men a, b and c is 84 kg. Another man d joins the group and the average weight now becomes 80 kg.if another man e replaces a then the average weight of b, c, d and e becomes 79 kgs.
I. What is the weight of D?
II. Find the weight of A?
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(a + b + c)/3= 84
So, a+b+c=252
(a+b+c+d)/4=80
So, 252+d=320
So, d=68
Weight of D is 68 kg
E replaces A and average becomes 79
(b+c+d+e)/4=79
So, (b+c+e)/4+(68/4)=79
So, (b+c+e)/4=79-17=62
So, b+c+e=248
As a+b+c=252
a+248-e=252
So, a-e=4
So, weight of A is 4 kg more than weight of E
So, a+b+c=252
(a+b+c+d)/4=80
So, 252+d=320
So, d=68
Weight of D is 68 kg
E replaces A and average becomes 79
(b+c+d+e)/4=79
So, (b+c+e)/4+(68/4)=79
So, (b+c+e)/4=79-17=62
So, b+c+e=248
As a+b+c=252
a+248-e=252
So, a-e=4
So, weight of A is 4 kg more than weight of E
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