Answer:
0.64
Explanation:
If it is at least one day than it could be once or twice.
multiply to find the probabilities of each day with walking and then add them
WW= 0.6 x 0.1 = 0.06
WB= 0.6 x 0.9 = 0.54
BW= 0.4 x 0.1 = 0.04
Then add these together
=0.64