Question

10 % of x + 20% of y = 24 And 3x - y =20. findx and y​

Answer 1

Answer:

x=40 and y=100

Step-by-step explanation:

(10/100)*x+(20/100)*y=24

x/10+2y/10=24

x+2y=240 let this be eqn 1

also

3x-y=20 let this be eqn 2

solving 1 and 2

x=40 and y=100

Answer 2

$\sf{10 \% \:of\: x + 20\% \: of\: y = 24}\\\\\\\longrightarrow \: \sf{\dfrac{10}{100}x + \dfrac{20}{100}y = 24}\\\\\\\longrightarrow \: \sf{\dfrac{x}{10} + \dfrac{2y}{10} = 24}\\\\\\\longrightarrow \: \sf{\dfrac{x+2y}{10} = 24}\\\\\\\longrightarrow \: \sf{x+2y = 24 \times 10}$

$\longrightarrow \: \bf{x+2y=240 \qquad \dashrightarrow [Equation 1]}$

Let's take the Second Equation now.

3x - y = 20    →  →  →  [Equation 2]

Multiply Equation 2 with 2

2(3x - y) = 2(20)

⇒ 6x - 2y = 40      →  →  → [Equation 3]

Adding Equation 1 and 2,

                     x + 2y = 240

            {+}   6x - 2y = 40

                           7x = 280

⇒ x = 280 ÷ 7

∴ x = 40

Substitute value of x in Equation 1 or 2 or 3 to find the value of y

3x - y = 20

⇒ 3(40) - y = 20

⇒ 120 - y = 20

⇒ y = 120 - 20

∴ y = 100