Question

17. (1) According to the question,
[
begin{array}{l}
A+B=20 times 2=40
B+C=19 times 2=38
C+A=21 times 2=42
end{array}
]
Adding all the three equations,
[
begin{aligned}
2(A+B+C) &=40+38+42
&=120
end{aligned}
]
( Rightarrow quad A+B+C=60 )
On subtracting Eq.
(ii) from Eq. (iv), we get
[
begin{aligned}
A &=(A+B+C)=-(B+C)
&=60-38=22
end{aligned}
]

# 17. The average of A and B is 20, average of B and C is 19 and average of C and A is 21. Find the value of A. (1) 22 (2) 20 (3) 18 (4) 24

Solution