#### Answer

The interval in which the graph is increasing is\[\left( 25,55 \right)\] and the interval in which the graph is decreasing is \[\left( 55,75 \right)\].

#### Work Step by Step

It can be observed from the given graph that at 25 years of age, the percent body fat in women is 34 and starts increasing and reaches 38 by 55 years of age.
Thus, the percent body fat in women is increasing in the interval $\left( 25,55 \right)$.
Also, at 55 years of age, the percent body fat in women is 38 and starts decreasing and reaches 36 by 75 years of age.
Thus, the percent body fat in women is decreasing in the interval $\left( 55,75 \right)$.