Mr. smith is having some photos enlarged for his studio he wants to enlarge a photo that is 5in by 7in so the dimensions are 3 times larger than the original what are the dimensions of the enlarged photo

9 times larger

The reason is simple, all you need to do is 7 x 3, and 5 x 3, giving you the l x w of 15 and 21 inches.  You multiply these numbers together, meaning the original length and width (l x w), which would be 5 and 7, which equals 35.

From here, you multiply 15 and 21, which gives you 315.

Divide 35 from 315, and see what you get!
Hope this helps!