Terry can run 15 miles in the same amount of time it takes mark to run 21 miles. if mark runs 2mph faster than terry, how fast does mark run?

The first week samantha learned to read braille, she could read 10 words per minute. in the second week she increased her speed by 20%. in the third week she increased her speed again by another 25%. how many words could she read per minute by the third week? hurry and tell me!