Help? math questions... i suck @ math...heheh?

plz dont just guess. thnx!


1] A hectare-metre is the volume required to coverone hectare of area 1 metre deep. The number of hectare-meters of water needed to cover a 62 1/2 hectare area with water 76 4/5 cm deep is


a]0.48 b]4.8 c]48 d]480 e]4800


2]Two concentric circles are such that one circle has half the radius of the other. If a point is chosen at random inside the larger circle, the probability that it also lands outisde the smaller circle is


a]1/4 b]1/2 c]3/5 d]2/3 e]3/4


3]There is only one four-digit number abcd that is equal to a exponent b X c exponent d. The sum of its digits is


a]18 b]20 c]21 d]24 e]29


4]The binary number 10111101two,written in ternary notation, is


a]21three b]210three c]2100three d]21000three e]210000three


5]When these rationals are listed in order from least to greatest, the next-to-last in the list is


a] -19/30 b] -17/26 c] -13/20 d] -15/23 e] -14/27


6]The surface area of a sphere w/ diameter 2 squareroot3 cm2 is


a]4pi b]12pi c]16pi d]24pi e]48pi


thnx

Help? math questions... i suck @ math...heheh?
1.


62 1/2 * 76 4/5 cm


= 62.5 * 76.8 cm


= 62.5 * 0.768 m


= 48


Correct answer us C





2.


Area of the smaller circle = (pi) r^2


Area of the bigger circle = (pi) (2r)^2 = 4 (pi) r^2





Probability that a point in the bigger circle is inside the smaller circle: (pi) r^2 / 4 (pi) r^2 = 1/4





Probability that a point in the bigger circle is outside the smaller circle: 1 - 1/4 = 3/4





Correct answer is E





3. I have to think about this one





4.


10111101(two) = 189(ten) = 21000(three)


Correct answer is D





5.


-19/30 = -0.63333


-17/26 = -0.65384


-13/20 = -0.65


-15/23 = -0.65217


-14/27 = -0.51851





In ascending order


-17/26, -15/23, -13/20, -19/30, -14/27





Correct answer is A





6.


Surface area of a sphere = 4 (pi) r^2


= 4 (pi) (2sqrt(3))^2


= 4 (pi) (4*3)


= 4 (pi) 12


= 48 (pi)





Correct answer is E





I hope this helped





Kia