Q6:

A box contains 10 light bulbs, fewer than half of which are defective. Two bulbs are to be drawn simultaneously from the box. If n of the bulbs in box are defective, what is the value of n?

(1) The probability that the two bulbs to be drawn will be defective is 1/15.

(2) The probability that one of the bulbs to be drawn will be defective and the other will not be defective is 7/15.

why?

Q10.In the figure shown, two identical squares are inscribed in the rectangle. If the perimeter of the rectangle is 18√2, then what is the perimeter of each square?

A. 8√2

B. 12

C. 12√2

D. 16

E. 18

ans:B I have no idea to calculate Q10

Q14:？

Box W and Box V each contain several blue sticks and red sticks, and all of the red sticks have the same length. The length of each red stick is 18 inches less than the average length of the sticks in Box W and 6 inches greater than the average length of the sticks in Box V. What is the average (arithmetic mean) length, in inches, of the sticks in Box W minus the average length, in inches, of the sticks in Box V?

A. 3

B. 6

C. 12

D. 18

E. 24

ans:E

please help me..thanks a lot!!!

Q6: 1, Cn,2/C10,2= 1/15; 2, Cn,1*C(10-n),1/C10,2 = 7/15

Q10: 2(l+w)=18SQR2 ; 2x^2=w^2 ; ===> l=2w ; x=3 ====>4x = 12

Q14: "all of the red sticks have the same length. The length of each red stick is 18 inches less than.... W" means: the average length in W = R + 18; follow the same strategy: the average length in V = R - 6 ====> W minus V =R+18-R+6 = 24