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Triangle XYZ is an equilateral triangle. YW‾ \overline{\rm YW} YW is an altitude of the triangle. If XY‾ \overline{\rm XY} XY is 10 in., what is the length of the altitude?

(A)5 in.

(B)5 √3 in.

(C)10 in.

(D)10 √3 in.

(E)5√2 in.

Scott's swimming pool has a depth of 8 feet and holds 13,000 gallons of water when full. Because of the warm weather, 10% of the water in the pool evaporates each day. Scott fills the pool with water and comes back the next day to measure the amount of water remaining in the pool. He considers this "Day 1" because it was taken 1 day after the pool was filled, and he labels his measurement as such. The next day, he measures the amount of water again, and he labels the results "Day 2" because it is now 2 days after he filled the pool. If Scott continues, on which day will he measure the pool that it is less than half full?

（A）5 （B） 6 （C） 7 （D） 8 （E） 9

Correct Answer: C

Which of the following is a possible value of xif 5x2– 10x+ 4 = 0?

(F) (G) (H) (J) (K)

Correct Answer: H

If 3(2x - 1) = 11x + 27, then x = ?

（A）-6 （B） -2 （C） 2 （D） 6 （E） 7

Correct Answer: A