Where the blue scribble is!
4+3x is what it sound like. I hope this helps. :)
Answer:
There is an 85% probability that the sprinkler head will be activated.
Step-by-step explanation:
We have these following probabilities:
50% of the first sprinkler being triggered
90% of the first sprinkler being reliable
50% of the second sprinkler being triggered
80% of the second sprinkler being reliable.
What is the probability that the sprinkler head will be activated?

is the probability of the first sprinkler being triggered and activated. So:

is the probability of the second sprinkler being triggered and activated. So:


There is an 85% probability that the sprinkler head will be activated.
I think it moves 5 units to the right Im not sure tho!!
B is the best strategy. (You mentioned an option D, but it's not shown in your question!!)