Question

$\text{The sum of three rational numbers is}\frac{-1}{5}.\text{If two numbers are}\frac{-2}{5}\text{and}\frac{3}{10},\text{then find}\text{the third number.}$

• A. $\frac{8}{10}$
• B. $\frac{1}{10}$
• C. $\frac{-1}{10}$
• D. $\frac{-2}{10}$

Answer 1

The correct option is C

$\frac{-1}{10}$

$\text{Let the unknown number be}x.$

$\frac{-1}{5}=\frac{3}{10}+\frac{-2}{5}+xx=\frac{-1}{5}-\frac{3}{10}+\frac{2}{5}$

$\text{Taking LCM, we get,}x=\frac{-2}{10}-\frac{3}{10}+\frac{4}{10}x=\frac{-1}{10}$