Question 252587
Check the Venn diagram below. (not drawn to scale)
The entire red circle is 50 as is the entire green circle 50.
The intersection of the circles is 11
The red circle left of the intersection is 50-11=39 as is the green circle right of the intersection=39
39+39+11=89 This is the union of the 2 circles which includes the intersection.
Out side this union but inside the rectangle is the final 11. They took neither history nor politics.
.78=probability that a student is taking history or politics but not both.
This is the answer correct for sure unless you copied the question wrong.
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Ed
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{{{drawing( 300, 300, -5, 5, -5, 5,
  rectangle( -4.5, 4.5, 4.5, -3.5 ),
red( circle(- 1.5, 0, 2.5) ),
  green( circle( 2, 0, 2.5 ) ))}}}