If a varies directly with b, write the constant of proportionality equation. b = 2 and a = 10
options:
1. a=5b
2. k=5
3. a= 1/5b
4. b=5a

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!