A) how many ways can the letters in the word computer be arranged in a row? b. how many ways can the letters of the word computer be arranged if the letters co must remain next to each other as a unit?

A.

The are 8 total letters:
8!= 8*7*6*5*4*3*2*1
=40320

B.

The are still 8 total letters, but the 1st 2 are constants, CO. So what would scramble the remaining letters as such.

6!= 6*5*4*3*2*1
=720

Hope this helps