A box contains 3 black pens, 7 blue pens and 5 red pens. Without replacing the first pen, what is the probability of pulling a red or blue pen?

12/15

Step-by-step explanation: first you add 7+5=12

then add 12+3=15

isaiah walks 3 miles due north, turns and then 5 miles due east. how far is he from his starting point?

a^2 + b^2 = c^2

let c = distance from starting point.

(3)^2 + (5)^2 = c^2

9 + 25 = c^2

34 = c^2

sqrt{34} = sqrt{c^2}

sqrt{34} = c