Question

. 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​

Answer 1

Step-by-step explanation:

$\bf{\underline{\underline\red{Given:-}}}$

• If twice the age of A is added to B's age, the
• sum is 45.

• If twice the age of B is added to
• A's age, the sum is 30.

$\bf{\underline{\underline\blue{To\:Find:-}}}$

• The age of B

$\bf{\underline{\underline\green{Solution:-}}}$

Let

The present age of B = x

And present age of A = y

According to the 1st condition:-

If twice the age of A is added to B's age, the

sum is 45

$\rm \implies x + 2y = 45.....(i)$

According to the 2nd condition:-

If twice the age of B is added to A's age, the sum is 30.

$\rm \implies 2x + y = 30.....(ii)$

Multiplying equation (i) with 2

$\rm \implies 2(x + 2y = 45)$

$\rm \implies 2x + 4y = 90.....(iii)$

Subtracting equation (ii) from (iii)

$\rm \implies (2x + 4y )- (2x + y) = 90 - 30$

$\rm \implies 2x + 4y - 2x - y = 60$

$\rm \implies3y = 60$

$\rm \implies y = \dfrac{60}{3} = 20$

Substituting y = 15 in equation (i)

$\rm \implies x + 2y = 45$

$\rm \implies x + 2(20) = 45$

$\rm \implies x +40 = 45$

$\rm \implies x = 45 - 5$

$\rm \implies x = 5$

$\boxed{ \rm \therefore Present \: age \: of \: B = 5years}$

Answer 2

Step-by-step explanation:

the age of B =x

the age of y =y

if twice the age of A is added to B age the sum is 45

x+y=45.......(1)

if twice the age of B is added to A age the sum is 30

2x+y=30

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