Chapter 3, Problem 18CP

To determine

To find: the expression which represent the area left to paint after $m$ minutes.

Answer to Problem 18CP

Correct option is G. $2850-45m$

Explanation of Solution

Given information:

Jay has already painted $200{\text{ ft}}^2$ and paints at the rate of $20{\text{ ft}}^2\text{ per minute}$ .

Maria has already painted $350{\text{ ft}}^2$ and paints at the rate of $25{\text{ ft}}^2\text{ per minute}$ .

Total area to paint is $3400{\text{ ft}}^2$ .

Jay has already painted $200{\text{ ft}}^2$ and Maria has already painted $350{\text{ ft}}^2$ .

So, total area which is left to paint is: $\left(3400-200-350\right){\text{ ft}}^2=2850{\text{ ft}}^2$

Jaypaints at the rate of $20{\text{ ft}}^2\text{ per minute}$ and Maria paints at the rate of $25{\text{ ft}}^2\text{ per minute}$ .

Let, $m$ be the time for which Jay and Maria painted.

So, total area painted by Jay after $m$ minute is $20m{\text{ ft}}^2$ and total area painted by Maria after $m$ minute is $25m{\text{ ft}}^2$ .

Total area painted by both of them is $\left(20m+25m\right){\text{ ft}}^2=45m{\text{ ft}}^2$

Hence,

Area left to pain after $m$ minute can be expressed as:

  $\left(2850-45m\right){\text{ ft}}^2$

Hence,

Correct option is G. $2850-45m$