Answer:
The probability of choosing a blue or yellow highlighter when one yellow highlighter is picked is 17/25.
Step-by-step explanation:
Here, according to the question:
Total number of yellow highlighters  = 12
Total number of blue  highlighters  = 6
Total number of green highlighters  = 4
Total number of orange  highlighters  = 3
So, the total number of highlighters  =  12 + 6 + 4 + 3  = 25
Let E1 : Event of selecting a yellow highlighter.
P(E1)  =  =
  = 
Let E2 : Event of selecting blue or yellow highlighter ONCE yellow highlighter is selected.
So, the total yellow highlighters left after selecting one = 12 -1  = 11
Also, the number of blue highlighter  =  6
So, the TOTAL FAVORABLE options to E2 = 6+ 11 = 17
P(E2)  = 
 =
 = 
Hence, the probability that a blue or yellow highlighter is selected given that a yellow highlighter is selected is 17/25.