ANSWER
Cam spent 1/2 of the day on these two things.
EXPLANATION
To know how much of the day he spent doing these two activities, we have to add the time he spent on each one:
[tex]\frac{2}{10}+\frac{3}{10}=\frac{5}{10}[/tex]And simplify the fraction. Both numerator and denominator can be divided by 5:
[tex]\frac{5}{10}=\frac{1}{2}[/tex]So he spent half the day in these activities.