[求助]请教3道PP数学题

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请教几道PP数学题

求助大牛们

 

 

1.

Which of the following lists the number of points at which a circle can intersect a triangle?

(A) 2 and 6 only

(B) 2, 4, and 6 only

(C) 1, 2, 3, and 6 only

(D) 1, 2, 3, 4, and 6 only

(E) 1, 2, 3, 4, 5, and 6

Ans:E

 

2.

[?]: line missed

(A) A certain list of 100 data has an average (arithmetic mean) of 6 and a standard deviation of d, where d is positive.  Which of the following pairs of data, when added to the list, must result in a list of 102 data with standard deviation less than d ?

(B) 0 and 0

(C) 0 and 6

(D) 0 and 12

(E) 6 and 6

Ans: 求此题思路

 

 

3.

A certain business produced x rakes each month from November through February and shipped 0.5x rakes at the beginning of each month from March through October.  The business paid no storage costs for the rakes from November through February, but it paid storage costs of $0.10 per rake each month from March through October for the rakes that had not been shipped.  In terms of x, what was the total storage cost, in dollars, that the business paid for the rakes for the 12 months from November through October?

(A) 0.40x  (B) 1.20x  (C) 1.40x  (D) 1.60x  (E) 3.20x

Ans: C