Official Quant thread for CAT 2013

@nick_baba said:
Let f(f(x)) = 2f(x) €“ x for all real x. If f(f(f(f(f(f(7)))))) = 0 then f(7) = ??
represent f(f(f(.....f(x)))))) i.e n times as fn(x)

In the given question we have f2(x) = 2f(x) - x

and f6(7) = 0
=>f6(7) = 2f5(7) - f4(7) = 2*{2f4(7) - f3(7)} - f4(7) = 3f4(3) - 2f3(7)
=3*{2*f3(7) - f2(7)} - 2f3(7)
=4f3(7) - 3f2(7)
=4{2f2(7) - f(7)} - 3f2(7)
=5f2(7) - 4f(7)
=5{2f(7) - 7} - 4f(7)
=6f(7)-35 = 0

=>f(7) = 35/6


ATDH.

@Shray14 said:
Kishore owns a factory of plastic goods. His production cost comprises only the cost of raw material and labour . The cost of raw material increases by 20% and the labour cost also increases from 20% to 25% of the cost of raw material. By how much percent should he reduce his consumption of raw material and labour so that his production cost remains unchanged?1)20%2)15%3)17%4)25%5)None of these
20 aayega
@nick_baba said:
bhai since mujhe numbers bht pasand hai to hm ise x k terms me na khelke numbers k terms me khelte hai..suppose raw material(R) cost 100 hai..to labor cost(L) 20 hui.to total production cost(p) 120 hui..now R cost 20% badi..so R is now 120...and L 20 se 25% badi..to 25% of 120= 30 huitherefore total cost 150 hui.now back to pavilion situation me 150 se 120 ana hai..means 30 reduce karna..which is 30/150==20%
Got it bro..
@anytomdickandhary said:
represent f(f(f(.....f(x)))))) i.e n times as fn(x) In the given question we have f2(x) = 2f(x) - xand f6(7) = 0=>f6(7) = 2f5(7) - f4(7) = 2*{2f4(7) - f3(7)} - f4(7) = 3f4(3) - 2f3(7)=3*{2*f3(7) - f2(7)} - 2f3(7)=4f3(7) - 3f2(7)=4{2f2(7) - f(7)} - 3f2(7)=5f2(7) - 4f(7)=5{2f(7) - 7} - 4f(7)=6f(7)-35 = 0=>f(7) = 35/6ATDH.
Chalo ab Sir ne answer pe apni mohor lagadi!! OA: 35/6 :P
@anytomdickandhary said:
represent f(f(f(.....f(x)))))) i.e n times as fn(x) In the given question we have f2(x) = 2f(x) - xand f6(7) = 0=>f6(7) = 2f5(7) - f4(7) = 2*{2f4(7) - f3(7)} - f4(7) = 3f4(3) - 2f3(7)=3*{2*f3(7) - f2(7)} - 2f3(7)=4f3(7) - 3f2(7)=4{2f2(7) - f(7)} - 3f2(7)=5f2(7) - 4f(7)=5{2f(7) - 7} - 4f(7)=6f(7)-35 = 0=>f(7) = 35/6ATDH.
ab to sir confirm ho gaya ..OA 35/6 hi hoga...ans source galat hoga..
@Shray14 said:
Kishore owns a factory of plastic goods. His production cost comprises only the cost of raw material and labour . The cost of raw material increases by 20% and the labour cost also increases from 20% to 25% of the cost of raw material. By how much percent should he reduce his consumption of raw material and labour so that his production cost remains unchanged?1)20%2)15%3)17%4)25%5)None of these
20%?
@ScareCrow28 said:
@deedeedudu chalo mere alawa bhi koi mistakes kara hai
Bhai double like nhi kar sakta tha isliye spam karna pad raha
PS:V rock
PPS:Shame on us
In triangle ABC, BE is drawn so that E lies on AC, and AD is drawn so that D lies on BC. AD and BE intersect inside the triangle at F. The area of ABC is 1, BD = DC and AE/EC = 2. What is AF/FD?
@nick_baba said:
In triangle ABC, BE is drawn so that E lies on AC, and AD is drawn so that D lies on BC. AD and BE intersect inside the triangle at F. The area of ABC is 1, BD = DC and AE/EC = 2. What is AF/FD?
4:1
Ab ye na bolna k galat hai dil toot jaega
The difference between simple interest and compound interest on a particular amount in 2 years at 30% is Rs.360. What is the principal?
1)Rs. 4000
2)Rs. 3500
3)Rs. 3000
4)Rs. 2500
5)None of these
@nick_baba said:
In triangle ABC, BE is drawn so that E lies on AC, and AD is drawn so that D lies on BC. AD and BE intersect inside the triangle at F. The area of ABC is 1, BD = DC and AE/EC = 2. What is AF/FD?
4
@Shray14 said:
The difference between simple interest and compound interest on a particular amount in 2 years at 30% is Rs.360. What is the principal?1)Rs. 40002)Rs. 35003)Rs. 30004)Rs. 25005)None of these
4000
Pr^2/10000=360
@Shray14 said:
The difference between simple interest and compound interest on a particular amount in 2 years at 30% is Rs.360. What is the principal?1)Rs. 40002)Rs. 35003)Rs. 30004)Rs. 25005)None of these
1.69P - 1.6P = 360
0.09P = 360
P = 4000
@nick_baba said:
In triangle ABC, BE is drawn so that E lies on AC, and AD is drawn so that D lies on BC. AD and BE intersect inside the triangle at F. The area of ABC is 1, BD = DC and AE/EC = 2. What is AF/FD?
4:1??
@deedeedudu HUHAHAHHA!!! tmne ulta nikal diaaa
@deedeedudu said:
1:4Ab ye na bolna k galat hai dil toot jaega
yaar man to kar rah hai bolne ka..tmne shayad FD:AF nikal diya hai..
@Shray14 said:
The difference between simple interest and compound interest on a particular amount in 2 years at 30% is Rs.360. What is the principal?1)Rs. 40002)Rs. 35003)Rs. 30004)Rs. 25005)None of these
4000

differnce in interest araises due to differnce in the interest on first year's interest.

SO .3x=360

x=1200 interest for 1 year

.3k=1200
k=4000 which is principal amount
@grkkrg said:
4
badiya bhai..
@Shray14 said:
The difference between simple interest and compound interest on a particular amount in 2 years at 30% is Rs.360. What is the principal?1)Rs. 40002)Rs. 35003)Rs. 30004)Rs. 25005)None of these
4000?
@ScareCrow28 said:
4:1??
@nick_baba said:
In triangle ABC, BE is drawn so that E lies on AC, and AD is drawn so that D lies on BC. AD and BE intersect inside the triangle at F. The area of ABC is 1, BD = DC and AE/EC = 2. What is AF/FD?
4:1
mpg