Question

The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that of B and C be 43 kg, then the weight of B is

Answer 1

if a+b+c/3=45 then a+b+c=135

if a+b/2=40 then a+b=80---1

b+c/2=43 then b+c=86---2

now by adding equation 1 and 2 we get a+2b+c=166 \

since a+b+c=135  135+b=166 b=166-135   which is 31 therefore the final answer is 31