We have
624 words ---- 12 min
x words ----- 20 min
x is the number of words typed in 20 min by Jamal
x can be calculated if we multiply 20 by 624 and then the result is divided between 12.

1040 words in 20 min
words Per-minute
624 words ---- 12 min
x words ---- 1 min
x is the number of words per minute
x can be calculated if we divided 624 between 12

52 words per minute
for example for 4 min
the number words will be 4x52=208 words
table
words minute
52 1
208 4
624 12
1040 20