A.P(both will decode the message)=0.70 * 0.80 = 0.56
B.P(at least one of them will decode the message)= 1- P(none of them will decode the message)= 1-(1-.70)(1-.80)=0.94
C.P(neither of them will decode the message)=(1-.70)(1-.80)=.06
Let the asking price is x, after reducing the asking price 10% it becomes .9x.
here, .9x=1953
so x=2170, which would make 40% profit.
so cost price is (100*2170)/140=1550 , which makes (1953-1550)=$403 profit
Hi tractable,
I don't know what to say. I think if you could manage a good night sleep before test night, surely you could manage your expected score. wish you all the best.