Question

Roby bought $4$ sofa chairs for $\$82$ and $2$ standard office chairs for $\$133$. Estimate the difference between the costs of one sofa chair and one office chair. (Round off to the nearest $10$.)

• A. $\$20$
• B. $\$40$
• C. $\$65$
• D. $\$45$

Answer 1

The correct option is D $\$45$

Let’s round off the cost of $4$ sofa chairs and $2$ standard office chairs.

The cost of $4$ sofa chairs is $\$82$.

$82$ lies between the tens $80$ and $90$. Since $82$ is closer to $80,\$82$ can be rounded off as $\$80$.

The cost of $2$ standard office chairs is $\$133$.

$133$ lies between the tens $130$ and $140$. Since $133$ is closer to $130,\$133$ can be rounded off as $\$130$.

Cost of $1$ sofa chair $=\frac{\$80}{4}=\$20$

Cost of $1$ standard office chair $=\frac{\$130}{2}=\$65$

Hence, the difference between the costs of one sofa chair and one standard office chair is $\$65-\$20=\$45$.