What percent is represented by the shaded area?

Aportion of a line bounded by two points is defined as

Find the percent error of the measurement 4 cm

One cell phone plan charges $20 per month plus $0.15 per minute used. a second cell phone plan charges $35 per month plus $0.10 per minute used. write and solve an equation to find the number of minutes you must talk to have the same cost for both calling plans.