I think you should go with A).
Answer:
3) 0.72
Step-by-step explanation:
The probability that tomorrow the Fed will cut interest rates (P(F)) OR the DJIA will go up (P(D)), is the sum of each event's individual probability minus their joint probability (Fed cutting interest rates AND the DJIA will going up, P(FD))

The probability that tomorrow the Fed will cut interest rates or the DJIA will go up is 0.72.
Solve for x
so assuming that the fractions are
(9/4)-(1/*2x))=4/x then
get all x on one side
add 1/(2x) to both sides
9/4=(4/x)+(1/(2x))
make common denomators with x and 2x
common denomenator is 2x
4/x times 2/2=8/(2x)
9/4=8/(2x)+1/(2x)
add
9/4=9/(2x)
make common denomators with 4 and 2x
common denomator is 4x
9/4 times x/x=9x/(4x)
9/(2x) times 2/2=18/(4x)
9x/(4x)=18/(4x)
multiply both sides by 4x to clear fraction
9x=18
divide both sides by 9
x=2