75 tickets have been sold so far.
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.
4 puzzles in 3 hours