the probability that event b occurs is 0.6, and the probability that events a and b both occur is 0.25. if the probability that either event a or event b occurs is 0.4, what is the probability that event a will occur?  Pick:	A) 0.05	B) 0.15	C) 0.45	D) 0.5	E) 0.55
<gadget id="calculator">0.25 + 0.4</gadget>
<output>0.65</output>

<gadget id="calculator">0.65 - 0.6</gadget>
<output>0.05</output>

<result>A</result>
the probability that event b occurs is 0.6, and the probability that events a and b both occur is 0.25. if the probability that either event a or event b occurs is 0.4, what is the probability that event a will occur?
subtract(add(0.25, 0.4), 0.6)
p ( a or b ) = p ( a ) + p ( b ) - p ( a n b ) 0.4 = 0.6 + p ( a ) - 0.25 p ( a ) = 0.05 ans : a