need some advice for some problems from BB 19 - 21

[benchy]

1. S is the sum of three consecutive integers, the greatest of which is x. In terms of S, which of the following is the sum of three consecutive integers, the least of which is X?

 

A. S - 6

B. S - 3

C. S + 3

D. S + 6

E 2S

 

Answer is D

(note : I try to plug in some numbers but the answer is C, how it comes to answer D??)

 

2. http://i70.photobucket.com/albums/i103/gu_ben/Aug1001.jpg

 

 

The figure above shows the lengths of the sides of an equiangular polygon. What is the area of the polygons?

 

A. 7

B. 8

C. 9

D. 14 root2

 

Answer is A

 

3. A certain recipe makes enough batter for exactly 8 circular pancakes that are each 10 inches in diameter. How many circular pancakes, each 5 inches in diameter and of the same thickness as the 10 inch pancakes, should the recipe make?

 

A. 4

B. 16

C. 24

D. 32

E. 40

 

Answer is D

 

4. If k is an integer and 5^k

 

A. 6

B. 7

C. 8

D. 9

E. 10

 

5. 0

 

Column A : n - m

Column B : n + m / 2

 

(The answer is D. However I try many numbers but all results are B, pls tell me what i have missed??)

 

6. A merchant made a profit of $2.75 on the sale price of a sweater that cost the merchant $12.25

 

Column A : The profit expressed as a percent of the cost to the merchant.

Column B : The profit expressed as a percent of the sale price.

 

The answer is A

 

Thank you in advance for providing helpful advising. Thanks :grad:

[ved]

1.

Consider a series S1 3,4,5 the total of these number is 12 the question says express the value of a Series S2 if the least value in S2 is the largest value from S1 so S2 = 5 ,6 ,7 total = 18

Now, to express S2 in terms of S1 the equation should be 12 + 6 = 18

hence S + 6

 

3.

The total amount of batter used is 8 * Area(5*5Pi) = 200 Pi

Desired amount of batter for new pancakes = 2.5*2.5*Pi

Total amount of pancakes = 200 Pi/6.25Pi = 32

 

 

4.

Requires a logical approach if we split 5 in two groups we have

625 * 625 now we know 600 * 600 = 36,00,00 doesn't fit the equation

so the value is less than 5^8 same approach for 5^7

 

 

5.

consider m = 2 n = 100 then

Column A is greater than B

other wise Column B is greater than A answer is D

 

6.

The profit merchant made was 2.75 cost was 12.25

Profit = sales - cost

therefore sales price is 15

 

profit as percentage of cost is 2.75/12.25 ~22%

profit as percentage of sales is 2.75/15 ~ 18%

 

Column A

[benchy]

Thank you Ved very much. :D

 

Could someone tell me about how to solve the number 2. question? I dunno how to split it until I get the right answer :)

[theGrin]

Consider the following partition...

...____

./| ...|\

/_|.. .|_\

| | . .| |

|_| ...|_|

\ | ...| /

.\|____|/

 

 

Because the problem says that the polygon is equiangular, it is not hard to see that each of the angles of the triangles (besides the 90o ones) measure 45o. Then the side of each triangle is 1 and the areas can be calculated in a straight forward manner...

 

 

Simple explanation about the 45o fact...

______

..../|b

.../a|

../. |

./c__|

|d

|

 

From the construction b and d are right angles (90o). As a + b and c + d make the angles of the polygon, and it is equiangular, a + b = c + d => c = a. As the other angle of the triangle is also right, c = a = 45o

 

(Damn, this forum messes up the spaces...)

 

[M98Ranger]

Man Grin!.....You beat me too it!....I finally found one I could help with!....Good explanation.

[benchy]

Thank you The GRin very much. :D you're one of the math master !!!