combination
Formula solving
speed solving
number sense
100
You flip 2 coins and roll 1 die. How many outcomes are possible?
24
100
A right triangle having three sides of 5,4,3. What is the area of the triangle.
6
100
Ara and Shea were once the same height. Since then Shea has grown 20% while Ara has grown half as many inches as Shea. Shea is now 60 inches tall. How tall, in inches, is Ara now?
55
100
152
225
200
A chess king is said to attack all squares one step away from it (basically any square right next to it in any direction), horizontally, vertically, or diagonally. For instance, a king on the center square of a 3 x 3 grid attacks all 8 other squares, as shown below. Suppose a white king and a black king are placed on different squares of 3 x 3 grid so that they do not attack each other. In how many ways can this be done?
32
200
There is a list of seven numbers. The average of the first four numbers is 5, and the average of the last four numbers is 8. If the average of all seven numbers is 
, then the number common to both sets of four numbers is.
6
200
The ratio of red paint to blue paint to green paint is 4:6:9. The amount of green paint there are is 36 gallons. What is the number of red paint?
16 gallons
200
Estimate 2^20, both team can answer, whoever is more close gets the point.
1048576
300
A cricket randomly hops between 4 leaves, on each turn hopping to one of the other 3 leaves with equal probability. After 4 hops, what is the probability that the cricket has returned to the leaf where it started? note: Make the answer a fraction.
7/27
300
What is the area of a square that has two diagonals of 12?
72
300
Rohan keeps a total of 90 guppies in 4 fish tanks. There is 1 more guppy in the 2nd tank than the 1st tank. There are 2 more guppies in the 3rd tank than the 2nd tank. There are 3 more guppies in the 4th tank than the 3rd tank.
How many guppies are in the 4th tank?
26
300
133
2197
400
Keiko tosses one penny and Ephraim tosses two pennies. The probability that Ephraim gets the same number of heads that Keiko gets is? note: it is a fraction
3/8
400
What is the units digit of
?
8
400
There are 5 people trying to cross a bridge. There can be only 2 people crossing the bridge each time. The time they use is 2, 4, 7, 10, and 12 minuets. Also, you need a torch held by someone when crossing the bridge. What is the shortest time the people would take?
35min
400
8!=?
6720
500
A lock is made up of four digits that satisfy the following rule. At least one digit is a four but neither the second digit nor the forth digit is a 4. Exactly one digit is a 2 but the first digit is not two. Exactly one digit is a 7. The code includes a 1, or the code includes a 6, or the code includes two 4s. How many codes are possible.
22 possible codes
500
What is the area of a triangle that has three sides of x*2 6/7, 2x/7, and 3x when x=14?
3sqrt559, you get half points for answering sqrt5031
500
There are 4 people, captured by a monster. The monster gave them four hats. There 2 black hats and two white hats. At least one of them need to guess their hat color correctly. Nobody will talk before they know their hat color. (The picture will be drawn) Is it possible to let them go if you are one of them. If so, please show your process.
It is possible. Prisoner A sees that there are two different hats he can see, so he can't determine the hat color on his head, so he stays quiet. Then, the prisoner B knows that Prisoner C's hat color is different from his. Thus, B will be able to know that he is wearing a black hat.
500
163
4096