Distinguish between the internet backbone and an internet service provider?

A backbone is a high-speed wide area network (WAN) connecting lower speed networks.

An Internet service provider (ISP) is an organization that provides services for accessing, using, or participating in the Internet.

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.