Question

Given $a=1\frac{5}{7},b=\frac{1}{4},c=\frac{1}{9}andd=(-1\frac{1}{4})$, Evaluate $a(b-c)÷d$.

• A. $\frac{-4}{21}$
• B. $\frac{-6}{23}$
• C. $\frac{-5}{27}$
• D. $\frac{5}{21}$

Answer 1

The correct option is A $\frac{-4}{21}$

$a=1\frac{5}{7},b=\frac{1}{4},c=\frac{1}{9},d=(-1\frac{1}{4})$
$\Rightarrow a=\frac{12}{7},b=\frac{1}{4},c=\frac{1}{9},d=-\frac{5}{4}$

$a(b-c)÷d$
$\Rightarrow \frac{12}{7}(\frac{1}{4}-\frac{1}{9})÷-\frac{5}{4}$
$\Rightarrow \frac{12}{7}\left(\frac{9-4}{36}\right)\times -\frac{4}{5}$
$\Rightarrow \frac{12}{7}\left(\frac{5}{36}\right)\times -\frac{4}{5}$
$\Rightarrow \frac{5}{21}\times -\frac{4}{5}$
$\Rightarrow -\frac{4}{21}$