Which percent change represents a percent increase?

Car a and car b were in a race .the driver of car b claimed that his car was twice as fast as car a

Solve 13 + w/7= -18 (w/7 is a fraction)

Reading tests are compared for two students. sara got 98, 100, 65, 78, 98, 46, 100, 100, 45, and 50 on her reading test. lee got 97, 67, 89, 99, 100, 45, 79, 89, 58, and 67 on his reading test.