How would i find the answer in ft/sec?

Question

A street light is at the top of a 14 ft tall pole. A woman 6 ft tall walks away from the pole with a speed of 8 ft/sec along a straight path. How fast is the length of her shadow increasing when she is 45 ft from the base of the pole?

Note: How fast the length of her shadow is changing IS NOT the same as how fast the tip of her shadow is moving away from the street light.

Answer 1

14/6 = (8t + l)/l; 7l = 3l + 24t; l = 6t; dl/dt = 6 ft/s.

So, length of shadow increasing with constant speed