TTGWD-2-6/2-20 MATH

jessiebetty

Q6:

 

 

一个半圆         20 ft

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The figure above shows the dimensions of a semicircular cross section of a one-way tunnel.  The single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel.  If vehicles must clear the top of the tunnel by at least ½ foot when they are inside the traffic lane, what should be the limit on the height of vehicles that are allowed to use the tunnel?

 

 

A.     5½ ft

B.     7½ ft

C.     8 ½ ft

D.     9½ ft

E.      10 ft

WHY B

谢谢拉

jessiebetty

Q20:

A collection of 36 cards consists of 4 sets of 9 cards each.  The 9 cards in each set are numbered 1 through 9.  If one card has been removed from the collection, what is the number on that card?

(1)     The units digit of the sum of the numbers on the remaining 35 cards is 6.

(2)     The sum of the numbers on the remaining 35 cards is 176.

                  

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

(1)为什么/

gg137

因为所有数之和是180 而拿掉一个数 这个数最大是9

 units digit of the sum of the numbers on the remaining 35 cards is 6  表明 SUM只能是176 不可能是166 或156 或更小 和最小就是180-9=171了

（1）等同于告诉你是176

carriexu

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