If twice the age of A is added to B’s age, the sum is 45 and if twice the age of B is added to A’s age, the sum is 30.
If twice the age of A is added to B’s age, the sum is 45 and if twice the age of B is added to A’s age, the sum is 30. Then the age of B is ………………
A) 20
B) 5
C) 10
D) 30
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Correct option is (B) 5
Let age of A be x & age of B be y.
Then according to first condition, we obtain
2x+y = 45 _______(1)
According to second condition, we obtain
x + 2y = 30 _______(2)
Multiply equation (2) by 2, we get
2x + 4y = 60 _______(3)
Subtract equation (1) from equation (3), we obtain
(2x + 4y) - (2x + y) = 60 - 45
\(\Rightarrow\) 3y = 15
\(\Rightarrow\) y = \(\frac{15}3\) = 5
Hence, the age of B is 5.
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