510 visitors in 30 hours or 960 visitors in 60 hours, which is greater

The 30 hours is greater.

Step-by-step explanation:

For the 30 hours :

For the 60 hours :

Thus the 30 hours is greater.

well there are two answers for that.

1: you need 120 ones then that will equal up to 120.

2: you could also do one 100 and 2 tens.

those are the answers that i have thought of.