G8 AMC practice 3

 $a@b=\frac{a+b}{ab}$  If we have a formula as this for positive integers a and b, then what is 5@10?

What is the sum of the mean, median, and mode of the numbers 3, 4, 1, 4, 2, 5, 1, 4?

Which of the following figures has the greatest number of lines of symmetry?

Using only pennies, nickels, and quarters, what is the smallest number of coins Freddie would need so he could pay any amount of money up to 99 cents?

A car leaves a town traveling at 40 mph. Two hours later, a second car leaves the same town, on the same road, traveling 60 mph. The second car drives how many hours to overtake the first car?

Of the 640 balls in a large bag, 85% are red and the rest are blue. How many of the red balls must be removed from the bag so that 75% of the remaining balls are red?

The hundreds digit of a three-digit number is 7 more than the unit digit. The digit of the three-digit number is reversed, and the resting number is subtracted from the original three-digit number. What is the unit digit of the final result?

Five pepperoni circles will exactly fit across the diameter of a 10-inch pizza when placed as shown. If a total of 10 circles of pepperoni are placed on this pizza without overlap, what fraction of the pizza is covered by pepperoni?

The two circles are concentric circles with center C. Chord AB is tangent to the inner circle at D and AB=22. Find the area between the two circles.

what is the correct ordering of the three numbers,