Question

Set up equations and solve them to find the unknown numbers in the following cases: When I subtracted 11 from twice a number, the result was 15.

Answer 1

$\large\dag \: {\underline{\underline{\sf{Given :}}}}$ When 11 is subtracted from twice a number, the result is 15.

$\large\dag \: {\underline{\underline{\sf{To~Find :}}}}$ What is the unknown number?

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$\bullet$ Let the unknown number be x.

Then,

⌬ Twice the number = 2 × x = 2x

When 11 is subtracted from it,

⌬ 2x - 11

$\bf{\underline{ \bigstar \: According~to~the~question,}}$

$\begin{lgathered} \\ : \: \implies \quad \sf 2x - 11 = 15 \end{lgathered}$

$: \: \implies \quad \sf{2x = 15 + 11}$

$: \: \implies \quad \sf{2x = 26}$

$: \: \implies \quad \sf{x = \dfrac{ \cancel{26}^{ \: 13} }{ \cancel{2}_{ \: 1} } }$

$: \: \implies \quad \mathfrak{\fbox{x = 13}}$

Therefore, the unknown number is 13.

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Let's verify the answer now...!

✇ Substituting x = 13, we get :

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$\looparrowright \: \sf{2x - 11 = 15}$

$\looparrowright \: \sf{2(13) - 11 = 15}$

$\looparrowright \: \sf{26 - 11 = 15}$

$\looparrowright \: \sf{15 = 15}$

Hence, verified. ✓