a nursery owner buys 9 panes of glass to fix some damage to his greenhouse the 9 panes cost 19.35 unfortunately he breaks 4 more panes while repairing the garage. what is the cost of another 4 panes?

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!