Average weight of A , B and C is 45, kg . If average weight of A and B is 40 ,kg and that of B and C

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

A

$17$

B

$20$

C

$26$

D

$31$

Solution

Weight of $A+B+C=45 \times 3=135 kg$…..$(1)$

Weight of $A+B=40 \times 2=80 kg$…..$(2)$

Weight of $B + C =43 \times 2=86 kg$…..$(3)$

Subtracting (2) from (1),

Weight of $C=135-80=55 kg$…..$(4)$

Subtracting (3) from (1),

Weight of $A=135-86=49$ kg…..$(5)$

Subtracting (5) from (2),

Weight of $B=80-49=31 kg$…..$(6)$

Standard 13

Quantitative Aptitude

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