delyan

Hi,ishti_du! I found the answer explanation for the question in NOVA-GRE book. Here it is: " Since there are twice as many townhomes as ranch-style homes, the probability of selecting a townhome is 2/3.* Now, “there are 3 times as many townhomes with pools than without pools.” So the probability that a townhome will have a pool is 3/4. Hence, the probability of selecting a townhome with a pool is (2/3)x(1/4)=(1/6) The answer is (E). * Caution: Were you tempted to choose 1/2 for the probability because there are “twice” as many townhomes? One-half (= 50%) would be the probability if there were an equal number of townhomes and ranch-style homes. Remember the probability of selecting a townhome is not the ratio of townhomes to ranch-style homes, but the ratio of townhomes to the total number of homes. To see this more clearly, suppose there are 3 homes in the subdivision. Then 2 would be townhomes and 1 would be a ranch-style home. So the ratio of townhomes to total homes would be 2/3. " That's the solution the authors of the problem provided - hope it will clarify how to solve such kind of problems! Regards, Delyan

Hi, ishtiaque! Yes, you are completely right - sorry for that stupid blunder :( I have edited my post with the correct answer. Anyway, I think that 1/2 is the right answer but let's wait just a little bit longer to see whether another suggestions will be posted. Regards, Delyan

Hi, ishti_du ! I have seen this problem before and I've also encountered some difficulties while trying to solve it but I finally succeded. The question is about what is the possibility to choose townhome with pools -so let's mark them with Y. It is stated that those type of homes are 3 times as many than those without pools - so we could express the number of the townhomes without pools as (Y/3). The total number of townhomes will be the sum of the two types of townhomes or : Townhomes= Y + (Y/3)=(4/3)Y We know also that the number of the townhomes is twice the number of the ranch-style homes or : Townhomes=2xRanch-style homes Solving this equation for the Ranch-style homes will gives us that: Ranch-style homes=Townhomes/2 We can substitute the value of the townhomes: Ranch-style homes=[(4/3)Y]/2=(4/6)Y Let's see what we have now: - Townhomes with pools=Y - Townhomes without pools=(Y/3) - Total number of townhomes=(4/3)Y - Ranch-style homes=(4/6)Y To find what is the possibility to select townhome with pools we should calculate the total number of homes or: - Total number of homes= All townhomes + Ranch-style homes= =(4/3)Y+(4/6)Y=(12/6)Y Now the final step is to calculate the possibility: Possibility=(Townhomes with pools)/(Total number of homes) or Answer=Y/[(12/6)Y]=6/12=1/2 Hope this explanation will help you to understand the solution of that problem! Wish you a lot of luck! Delyan

I think that the right answer for the first question is D - and let me show you my way of solving this problem ( maybe there is shorter and more time-saving way but that is the first solution that has come to me) Let's mark the initial number of bacteria with N. So at the beginning of the experiment we have N bacteria. After the addition of the antibiotic after 30s 1/3 of the bacteria will be dead, and the number of bacteria that are still alive would be: (N - 1/3N)=2/3N After another 30s or at the end of the 1st minute another 1/3 of the bacteria will be dead: 2/3N*1/3=2/9N and the number of the bacteria that are still alive would be: (2/3N-2/9N)=4/9N After 90s another 1/3 of the bacteria will be dead: 4/9N*1/3=4/27N and the number of the bacteria that are still alive would be: (4/9N-4/27N)=8/27N After the second minute we will have 8/27N*1/3=8/81N dead bacteria and finally in the culture there would be (8/27N-8/81N)=16/81 bacteria that are still alive. The right answer is D because the question asks what fraction of the original bacteria have been killed. After the period of 120s 16/81 of the bacteria are still alive, so the initial number of the bacteria is 81/81 and after substracting 16/81 from 81/81 we will have the fraction of the killed bacteria - 65/81 and I think that this is the correct answer.

Hi, Paras Chopra!!! A close friend of mine graduated from KGI in 2006 and now works for "Kythera Biopharmaceuticals, Inc." http://www.kytherabiopharma.com - her salary is around 65K which is pretty enough for a young specialist in US. The MBS program is an unusual combination of MS+MBA with strong science emphasis. The MBA element in the curriculum provides immediate after-graduation job placement in industry. The first year is dedicated to intensive core curriculum courses, the second year students work on TMP(Team Master Project) - small groups of students work together on a project in a bio company. My friend is very pleased with the program and she started her job within two months after graduation. Good Luck! Delyan :)