There are 500 tickets for sale in a raffle. tickets cost $3 each, or $20 for a book of 10. all 500 tickets were sold, and $1350 was raised. how many books of 10 tickets were sold?

15 booklets of 10 tickets each were sold.  

Step-by-step explanation:

We are given the following information:

Let x be the number of single tickets sold and y be the number of booklets sold.

Each booklet consist of 10 tickets.

There are total of 500 tickets.

Thus, it can be represented by the equation:

The cost of single ticket = $3

Cost of booklet = $20

Total money raised = $1,350

This, can be represented in the equation:

Now, we have obtained two equation in two variable. Solving these equations, we get:

Thus, 15 booklets of 10 tickets each were sold.

stops on an even number.

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.