Question

If x is directly proportional to y, x1=10 ,y1=210 and x2=20 ,then find y2=?

Answer 1

$Given \:x \propto y$

/* We know that */

$\frac{x_{1}}{y_{1}} = \frac{x_{2}}{y_{2}}$

$Here , x_{1} = 10 , y_{1} = 210$

$x_{2} = 20 , \: and\: y_{2} = ?$

$\frac{10}{210} = \frac{20}{y_{2}}$

$\implies y_{2} = 20 \times \frac{210}{10}$

$\implies y_{2} = 420$

Therefore.,

$\red{ Value \:of \; y_{2}} \green { = 420 }$

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Answer 2

$\bf{\underline{\underline{\bigstar\bigstar\: Given : }}}$

$\:\:$

• $\footnotesize{ x \propto y }$

• $\footnotesize{ {x}_{1} = 10, {y}_{1} = 210,{x}_{2} = 20 }$

$\:\:$

$\bf{\underline{\underline{\bigstar\bigstar\: To \: Find : }}}$

$\:\:$

• $\footnotesize{ {y}_{2} }$

$\:\:$

$\bf{\underline{\underline{\bigstar\bigstar\: Solution :}}}$

$\:\:$

$\footnotesize{ {x}_{1}:{y}_{1}::{x}_{2}:{y}_{2}}$

$\footnotesize{\implies \dfrac{{x}_{1}}{{y}_{1}}=\dfrac{{x}_{2}}{{y}_{2}}}$

$\footnotesize{\implies \dfrac{10}{210} = \dfrac{20}{{y}_{2}}}$

$\footnotesize{\implies \dfrac{1}{21} = \dfrac{20}{{y}_{2}}}$

$\footnotesize{\implies {y}_{2} = 21 \times 20}$

$\footnotesize{\implies {y}_{2} = 420}$

$\:\:$

$\bold{\underline{ {y}_{2} = 420}}$