gokhale:sec B q5.

[Chinni18]

@Tim: Q7, SEC C I took 1/3^n and 1/2^n as individual GPs and summed up in the usual manner. Then multiply with the respective coefficients afterwards

[tim]

hey i cud solve the 1st series and m gettng the answer as 3/2.
i m nt able to solve 2nd series....cn u temme how to do that one ?

[tim]

i heard that we r supposed to write some essay in one of the sections...so is that true ?

[Chinni18]

The second series is
7[ 1/3 + 1/(3^2) +1/(3^3) +........] -4[ 1/2 +(1/2^2) + 1/(2^3) + ..........]
Using the formula for sum to infinity of  a GP
7 [(1/3)/{1-(1/3)} -4[(1/2) / {1-(1/2)}]
=7(1/2) - 4(1)
=7/2 - 4
= -1/2

[Chinni18]

I believe there is indeed an essay, but I don't know for sure because it doesn't say so anywhere in the brochure, and it's only a two-hour exam anyway. I'm clueless as to the length, weightage etc.

[tim]

ok thnk u :)

[ritu]

its option b coz yes we shud equate p=ma....the mc of operating at day time is 30+10 =40 per bus....and mc at night is 60 coz caital cost has to be spent once only....
so 40 and 60

[aditi5000]

Brilliant Ritu :) Thanks!!!! It was there all along..

[Chinni18]

Ritu that's awesome!! Gosh I feel so dumb right now, the answer staring me in the face. There wasn't even any solving/equating required! Thank you!

[Chinni18]

I have a rather stupid doubt.. In the same transport question, if an option was given as Pd=30 and Pn=70, would that also be okay?

[aastha]

@ tim :

yes , you are generally supposed to write an essay on some current economic issue which is usually for 12 to 15 marks ....