3. Marija often visits her grandmother. Sometimes she goes on foot, and sometimes by bicycle. If she goes one way on foot and returns by bicycle, it takes her a total of $\frac{3}{4}$ of an hour. If she goes both ways by bicycle, it takes her a total of $\frac{1}{4}$ of an hour. How many minutes in total will she need if she goes both ways on foot?
3. Since Maria covers both directions by bicycle in $\frac{1}{4}$ of an hour, one direction is covered in $\frac{1}{4} : 2 = \frac{1}{4} \cdot \frac{1}{2} = \frac{1}{8}$ of an hour. $\quad 3$ POINTS Furthermore, since Maria covers one direction by bicycle and one direction on foot in $\frac{3}{4}$ of an hour,

it follows that one direction on foot is covered in $\frac{3}{4} - \frac{1}{8} = \frac{5}{8}$ of an hour.

3 POINTS

Therefore, Maria covers both directions on foot in $2 \cdot \frac{5}{8} = \frac{5}{4}$ hours, which is $\frac{5}{4} \cdot 60 = 5 \cdot 15 = 75$ minutes.

$4$ POINTS

TOTAL 10 POINTS