Answer:
20 cameras.
Explanation:
We have been given the dimensions of a store as
. We are also told that each security camera covers 400 sq ft.
First of all, we will find the area of store by multiplying its dimension as:
![\text{Area of the store}=130\text{ ft}* 60\text{ ft}](https://img.qammunity.org/2020/formulas/mathematics/high-school/plxhd5h0s8n8lquot99xbck812eft8kg99.png)
![\text{Area of the store}=7800\text{ ft}^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/djcxypq2jxyrodko6fzj6rxrqxm2fg0vct.png)
To find the number of camera it will need to cover the whole store, we will divide the total area of store by the area covered by each camera.
\
![\text{Cameras required to cover the whole store}=(78)/(4)](https://img.qammunity.org/2020/formulas/mathematics/high-school/3vckzvntwtqydzcba77q8b17osv9uz0gvz.png)
Since we can not purchase 0.5 of a camera, so we will round up our answer.
Therefore, we need 20 cameras to cover the whole store.