Line L1 has gradient 2 and is perpendicular to line L2. Line L2 passes through the point P(2, 1). Find the x-coordinate of the point where L2 meets the x-axis.

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!