To start this question, we should know what is the atomic number of cobalt. The atomic number (the number of protons) of Cobalt is Z =27.
Now, we know that a Cobalt 60 isotope means an isotope of Cobalt whose Atomic Mass is 60.
Thus, in a Cobalt 60 isotope, the number of neutrons in the nucleus are

From the question we know that the given nuclear mass is 59.933820 u.
Now, the mass defect of Cobalt 60 can be easily calculated by adding the masses of the protons and the neutrons as per our calculations and subtracting the given nuclear mass from it.
Thus,
Mass Defect = (Number of Protons Mass of Proton given in the question) + (Number of Neutrons Mass of Neutron given in the question)-59.933820 u

Thus, the required Mass Defect is 0.5634u.
In eV, the Mass Defect is 
$31.85
$49 multiply by .35 = 17.15
$49-17.15 = $31.85
Answer:
A) Check the first two: 2(x+5) and 2(x) + 2(5)
B) Check the last one: 14y + 2
Answer:
The system of inequalities that represents this situation is:
x+y≥10
6x+4y≤50
Step-by-step explanation:
As the statement says that Laura wants to provide one party favor per person to at least 10 guests, the first inequality would indicate that the number of stuffed animals plus the number of toy trucks should be equal or greater than 10:
x+y≥10
Also, the statement indicates that miniature stuffed animals cost $6.00 each and the toy trucks cost $4.00 each and that Laura has $50. From this, you would have an inequality that indicates that 6 for the number of miniature stuffed animals and 4 for the number of toy trucks would be equal or less than 50:
6x+4y≤50
The answer is that the system of inequalities that represents this situation is:
x+y≥10
6x+4y≤50