n a survey of teenagers, 2/3 responded that they got regular exercise, and 4/5 of those said that walking was their main form of exercise. What fraction of the teenagers mainly exercise by walking?
To find the fraction of teenagers who mainly exercise by walking, we need to multiply the fractions of those who responded and those who walk. The fraction of teenagers who got regular exercise is 2/3, and the fraction of those who walked as their main form of exercise is 4/5.
Multiplying the fractions, we have:
(2/3) * (4/5) = 8/15
Therefore, 8/15 of the teenagers mainly exercise by walking.