 XP Math - Forums - View Single Post - This is about MathCounts 05-02-2010   #13
MAS1   Join Date: Dec 2008
Posts: 249 Quote:
 Originally Posted by shadow123blast 10 points for the 1st person who answers all correctly
6. How many of the letters in MATHCOUNTS have a horizontal line of symmetry?
H, C, O so 3 letters.

7. Billy takes two marbles, without replacement, from a bag that contains only six yellow marbles and three blue marbles. What is the probability that he gets one marble of each color? Express your answer as a common fraction.
1/2

8. What is the volume, in cubic units, of a cube whose surface area is 600 square units?
S.A. of a cube = 6s^2 where s is the edge length of the cube.
600 = 6s^2
100 = s^2
s = 10
Volume = s^3 = 10^3 = 1000 cubic units

9. The only garments that a particular factory produces are dresses and shirts. It produces three dresses for every five shirts it makes. If the factory produced a total of 72 garments today, how many dresses did it make?
3 dresses for every 5 shirts makes a total of 8 garments.
72/8 = 9
3 x 9 + 5 x 9 = 27 + 45 = 72
So the factory made 27 dresses.

10. What is the number that yields the same value when it is multiplied by three and then increased by five as when it is multiplied by five then decreased by three?
3N + 5 = 5N - 3
8 = 2N
N = 4 