All we need to do is find out how many words they can both type per minute, WHICH we can do byyy:
Carrie:
787 / 12 = 65 (It's actually a decimal but we're just gonna keep it at 65)
Heather:
1020 / 15 = 68
SO, Heather can type 68 words per minute whereas Carrie can only type 65. Meaning Heather can type faster :D