D. 0.75 is the correct answer
explanation- 2 out of the 8 tiles are not blue A. so 6 out of 8 tiles would round equal 75% chance of not getting a blue A tile
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120 grams half life at 45 days would be 60 then half life of 60 in another 45 days (90 total) should be 30 grams
D=number of dogs
c=cats
d equals 4 less than 2 times c
d=-4+2c
20 dogs
d=20
subsitute
20=-4+2c
add 4
24=2c
divide 2
12=c
12 cats
