official quant thread for cat08

[MaskedMenace]

Originally Posted by MaskedMenace

v get y=[(1+k)/(1-k)]x line for k>1

Consider a regular polygon of p sides .The number of values of p for which the polygon will have angles whose values in degrees can be expressed in integers?

(a) 24 (b) 23 (c ) 22 (d) 20 (e)21

[masoom]

Originally Posted by MaskedMenace

Consider a regular polygon of p sides .The number of values of p for which the polygon will have angles whose values in degrees can be expressed in integers?

(a) 24 (b) 23 (c ) 22 (d) 20 (e)21

well i had done this way..

the exterior angle of a recular polygon is 360/p...

where p is the number of sides...

for internal angle to integer.. external should also be..

now 180 = 3^2 * 2^3 * 5..

so total number of facors = 3*4*2= 24..

barring p=1, p=2...

we have 22values of p...

[ankaj]

Originally Posted by MaskedMenace

Consider a regular polygon of p sides .The number of values of p for which the polygon will have angles whose values in degrees can be expressed in integers?

(a) 24 (b) 23 (c ) 22 (d) 20 (e)21

is the answer 21??? calculated all the values...may be missed some thing

another way is 180 has 18 factors... and rest values will be once which when divided by 180*2 or 180*3 should not leave any reminder...

[ankaj]

Originally Posted by masoom

well i had done this way..

the exterior angle of a recular polygon is 360/p...

where p is the number of sides...

for internal angle to integer.. external should also be..

now 180 = 3^2 * 2^3 * 5..

so total number of facors = 3*4*2= 24..

barring p=1, p=2...

we have 22values of p...

wrong post....

[MaskedMenace]

Originally Posted by ankaj

is the answer 21??? calculated all the values...may be missed some thing

another way is 180 has 18 factors... and rest values will be once which when divided by 180*2 or 180*3 should not leave any reminder...

Each angle in degrees is 180(p-2)/p.

180-{360}/{p}=k, so 360/p has to be an integer.
Factors of 360 = 2^3.3^2.5^1
So there are 4.3.2 solutions, but we exclude 1 and 2, because p>= 3
So, 24 -2 =22

[masoom]

Originally Posted by ankaj

massom bhai...

should it not be 3^2* 2^2*5= 9*4*5=180...this gives 18 factors....

ankaj bhai...

i ma taking the exterior angles...

exterior angles are given as 360/n..

[MaskedMenace]

Richard wrote all the possible two-digit numbers such that whenever one of the two digits is prime, the other is even ,and whenever one of the two digits is even, the other is prime. How many two-digit numbers did he write in all?

a. 35 b. 37 c. 39 d. None

[masoom]

Originally Posted by MaskedMenace

Richard wrote all the possible two-digit numbers such that whenever one of the two digits is prime, the other is even ,and whenever one of the two digits is even, the other is prime. How many two-digit numbers did he write in all?

a. 35 b. 37 c. 39 d. None

is the ans is 35..

[MaskedMenace]

Originally Posted by masoom

is the ans is 35..

naah ....

A distance between two stations P and Q is 120 km.A train starts from P to Q at 9:00 am with the speed of 40km/hr while other starts from Q to P at 10:00 am with speed of 40km/hr. After one hour first train halts at station for 15 min before starting its journey again but 2nd train does not halt anywhere.At what time trains meet?

[ahaprashant]

Originally Posted by MaskedMenace

Richard wrote all the possible two-digit numbers such that whenever one of the two digits is prime, the other is even ,and whenever one of the two digits is even, the other is prime. How many two-digit numbers did he write in all?

a. 35 b. 37 c. 39 d. None

Answer: None (31)

Correct ?