In a normal distribution what percent of values fall within one standard deviation of the mean?
19.1%
15%
30%
68.2%

75 tickets have been sold so far.

step-by-step explanation:

in this question it is clearly mentioned that 45 children's tickets have been sold and this number is 60% of the total tickets sold.

now let's assume the total number of tickets sold be x.

then 60% of x = 45

⇒

⇒ x(.6) = 45

by dividing with .6 on both the sides of the equation

⇒ x = 75

therefore 75 tickets have been sold so far.

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons