Marcario should use 4 pounds of macadamia nuts and 8 pounds of almonds.
Explanation
given
cost of macadamia nuts per pound=$9
cost of almond nuts per pound=$5.25
cost of the mixture per pound=$6.5
total pounds of the mixture to be made=12
let the pounds of macadamia nuts=x
pounds of almond nuts=y
total pounds of nuts=x+y=12

solving (1) and (2)
x=4
y=8
The definition of two events being mutually
exclusive (or disjoint) only means that it is not possible for the two events to
occur together. Given two events, E and F, they are mutually
exclusive and also mean independent.
In this case, since events E and F are mutually
exclusive, therefore the probability that either E or F will occur will simply
be the sum of two events.
P (E or F) = P (E) + P (F)
P (E or F) = 0.25 + 0.51
P (E or F) = 0.76
Therefore this means that there is a 76% probability that
either E or F will occur.
The lenght would be 12*4 is 48
Pythagorean Theorem A2+B2=C2
625=25+C2
600=C2
Square root of 2 each side
10 Square root of 6 Or 24.494897