Answer: D
Solution:
Clearly the arrow marks a value between 10.25 and 10.5, so only C and D are possible.
Looking, we see that the arrow is closer to 10.3.
Answer: C
Solution:
Converting the decimals to fractions, this is 8* 1/4 * 2 * 1/8=1/2.
Answer: D
Solution:
Each of the fractions simplify to 1/10, so this sum is: 1/10+1/10+1/10=3/10=0.3.
Answer: B
Solution:
If, for a moment, we disregard the white squares, we notice that the number of black squares in each row increases by 1 continuously as we go down the pyramid. Thus, the number of black squares is 1+2+…+8.
Same goes for the white squares, except it starts a row later, making it 1+2+…+7.
Subtracting the number of white squares from the number of black squares, (1+2+3+…+8)-(1+2+3+…+7)=8.
Answer: C
Solution:
We have that 20 +<ABC+<CBD=160, since <CBD =90, we have<ABC=140-90=50.,
Answer: E
Solution:
=0.008/0.0004=80/4=20.
Answer: B
Solution:
=2.5*8.1*10=200
Answer: B
Solution:
The decimal point of 0.075 is three away from what Betty punched in, and that of 2.56 is two away. The decimal point is therefore 3+2=5 units to the left of where it should be, so we would want 0.19200
Answer: D
Solution:
The first triangle has two legs of length sqrt(5), the second has two legs of length 2, the leg lengths of the third triangle are 2, sqrt(5), sqrt(13), two legs of the fourth triangle have length sqrt(10), and two legs of the fifth triangle have length sqrt(5). Therefore all of the triangles in the diagram except the third are isosceles, and there are 4 are isosceles.
Answer: A
Solution:
Note that the remainder of 60/7 is 4. We count 4 days past Thursday, and arrive at Monday.
Answer: E
Solution:
Note that if 1<=a<b<c, then sqrt(a)<sqrt(b)<sqrt(c). since 1<144<164<169, we can say that 12<sqrt(164)<13.
Answer: C
Solution:
We want the cost per person, which is 20,000,000,000/250,000,000=20,000/250=80.
Answer: D
Solution:
The circumference of the patio is 2*Pi*12=24*Pi=75.4. Since the bushes are spaced 1 foot apart, about 75 are needed.
Answer: E
Solution:
36=6*6; 6+6=12； 36=4*9； 4+9=13； 26=2*18； 2+18=20； 36=1*36； 1+36=37.
Answer: C
Solution:
1/2+1/3=3/6+2/6=5/6； the reciprocal of 5/6 is 6/5.
Answer: E
Solution:
We can put in 6 by leaving out the three boxes in one of the main diagonals.
Answer: B
Solution:
Looking at the diagram, the shaded region is the union of two rectangles, with a small rectangle as overlap. If we just add the areas of the two rectangles, then we'll overcount the small rectangle, so we must subtract that area to get the desired area.
The areas of the two larger rectangles are 2*10=20 ， 3*8=24, the area of the small rectangle is 2*3=6. The desired area is thus 20+24-6=38.
Answer: C
Solution:
(6*150+4*120)/10=138
Answer: A
Solution:
To get from the 1st term of an arithmetic sequence to the 100th term, we must add the common difference 99 times. The first term is 1 and the common difference is 5-1=9-5=13-9=…=4, so the 100th term is 1+4* 99=397.
Answer: C
Solution:
Let the amount of coffee the maker will hold when full be x. then 36%*x=45 => x=125.
Answer: C
Solution:
The possible medians after n is added are 6, n, or 9.
Case 1: the median is 6 (n<6): (3+n+6+9+10)/5=6 =>n=2;
Case 2: the median is n(6<n<9): (3+6+n+9+10)/5=n => n=7;
Answer: E
Solution:
Let the original price of an item be x. the sale price now is 1.25*x*0.8=x, which is the same as the original price.
Answer: D
Solution:
For every disks she sells, she profits 5/4-5/3=5/12. She needs to profit $100, so she needs to sell 100/(5/12)=100*12/5=240 disks.
Answer: A
Solution:
Alternately, we can simply keep track of the "bottom" side of the square. In the diagrams below, this bottom side is shown in red. (left)
Answer: A
Solution:
From 1 to 9, the times will be of the form a:ba. There are 9 choices for a and 6 choices for b, so there are 9*6=54 times in this period.
From 10 to 12, the minutes are already determined, so there are only 3 times in this case.
In total, there are 54+3=57 palindromic times.
AMC培训、答疑，请联系微信 / 电话：136 1118 1627
艾蕾特教育 @Elite Edu, 在这里，