Jennifer Has Made A Rectangle Using 48 Square Tiles. If She Adds The Length And Width Of Her Rectangle Together She Will Get A Prime Number. What Is The Length And Width Of Jennifer's Rectangle? Explain Your Reasoning.

48 = 1*48 = 2*24 = 3*16 = 4*12 = 6*8 (these are the ways 48 can be factored into a product of two numbers)
1 + 48 = 49 = 7*7 (not prime)
2 + 24 = 26 + 2*13 (not prime)
3 + 16 = 19 (prime) 4 + 12 = 16 = 4*4 (not prime)
6 + 8 = 14 = 2*7 (not prime)

Jennifer's rectangle is 16 tiles long and 3 tiles wide. These numbers multiply to 48 and add to a prime number, as the problem requires.