Question

If $8.5-\{5\frac{1}{2}-(7\frac{1}{2}+2.8÷x\left)\right\}\times 4.25÷(0.2{)}^2=306$, then the value of $x$ is

• A. $1.75$
• B. $3.5$
• C. $7$
• D. $1.4$

Answer 1

The correct option is B $3.5$

$8.5-\{5\frac{1}{2}-(7\frac{1}{2}+2.8÷x)\}\times 4.25÷{\left(0.2\right)}^2=306$

$\Rightarrow 8.5-\{\frac{11}{2}-\frac{15}{2}-\frac{2.8}{x}\}\times \frac{4.25}{{\left(0.2\right)}^2}=306$

$\Rightarrow 8.5-\{-2-\frac{2.8}{x}\}\times \frac{425}{4}=306$

$\Rightarrow 8.5-306=\{-2-\frac{2.8}{x}\}\times \frac{425}{4}$

$\Rightarrow 297.5=\{2+\frac{2.8}{x}\}\times \frac{425}{4}$

$\Rightarrow 2.8=2+\frac{2.8}{x}$

$\Rightarrow 0.8=\frac{2.8}{x}$

$\Rightarrow x=3.5$