Answer:
Sally needed 330 pages of album to place her photos in it.
Step-by-step explanation:
Given:
Total number of photos = 1000
Number of photos kept aside to be place in frame = 10
Number of photos in per page of album = 3
We need to find the number of pages needed to place the photos in album.
Solution:
First we will find the number of photos to be place in album.
Now we know that she kept aside some photos which has to be frame framed.
So number of photos to be place in album can be calculated by Subtracting Number of photos kept aside to be place in frame from Total number of photos
framing in equation form we get;
number of photos to be place in album = 1000 - 10 = 990 photos
Now we will find number of pages needed to place the photos in the album.
number of pages needed to place the photos in the album can be calculated by dividing number of photos to be place in album with number of photos in per page of album.
framing in equation form we get;
number of pages needed to place the photos in the album = 
Hence Sally needed 330 pages of album to place her photos in it.
