Gujarat BoardEnglish MediumSTD 7MATHSExponents2 Marks
Question
By what number should $(-20)^{-1}$ be divided to obtain $(-10)^{-1}$ ?
✓
Answer
Let the required number be $x.$
$(-20)^{-1}\div \text{x}=(-10)^{-1}$
$\Rightarrow \frac{1}{(-20)}\times \frac{1}{\text{x}}=\frac{1}{(-10)}$
$\Rightarrow \frac{1}{(-20\text{x})}=\frac{1}{(-10)}$
$\therefore \text{x}=\frac{(-10)}{(-20)}=\frac{1}{2}=2^{-1}$
Hence, the required number is $2^{-1}$.
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