## Quant Questions

How to solve the following two questions Q1. Find the greatest number that will divide 640, 710 and 1526 so as to leave the reminders 11, 7 and 9 respectively? a. 35 b. 37 c. 42 d. 47 Q2. 10% of a mixture of alcohol and water replaced with water. If the resulting ratio of alcohol and water in the new mixture is 2 : 5 , what was the alcohol and water in the ratio in the original solution? a. 4:9 b. 4:5 c. 20:43 d. 31:49 Both are from Career launcher take off. The solutions given are very confusing

## when we divide 640, 710 and

when we divide 640, 710 and 1526 by a given number it leave the reminders 11, 7 and 9 respectively..... so the given number will exactly divide (640-11) , (710-7) , (1526-9) ie) it will exactly divide 629 , 703 , 1517 nd thaat no will be the hcf of these 3 number .... which comes out be 37

## correct answer is 37 for the

correct answer is 37 for the first qus

## Dont know but how did you

Dont know but how did you get I would like to know the process rather than the answer

## i think incognto's methid is

i think incognto's methid is good enough

## Properties of H.C.F. and L.C.M.

Property 1: The greatest number that divides each of a, b and c leaving the same remainder in each case is H.C.F. of |a – b|, |b – c|, |c – a|. Example 1: The greatest number that will divide 132, 100 and 36 leaving the same remainder in each case is: a) 8 b) 24 c) 32 d) 64 Solution: In the given example, a = 132, b = 100 and c = 36 |a – b| = |132 – 100| = 32 |b – c| = |100 – 36| = 64 |c – a| = |36 – 132| = 96 Hence the required number = H.C.F. of 32, 64 and 96 which is equal to 32. Hence 32 is the greatest number that divides each of the numbers 132, 100 and 36 to leave the same remainder in each case and it can be verified that the remainder is 4 in each case. Example 2: Find the largest number that will divide 171, 333 and 576 to leave exactly the same remainder in each case. a) 9 b) 162 c) 27 d) 81 Solution: In the given example, a = 171, b = 333 and c = 576 |a – b| = |171 – 333| = 162 |b – c| = |333 – 576| = 243 |c – a| = |576 – 171| = 405 Hence the required number = H.C.F. of 162, 243 and 405 which is equal to 81. Hence 81 is the greatest number that divides each of the numbers 171, 333 and 576 to leave the same remainder in each case and it can be verified that the remainder is 9 in each case. Thank You Ravi Raja

## Property 2:

Property 2: The greatest number that divides each of a, b and c to leave remainders p, q and r respectively is H.C.F. of (a – p), (b – q), (c – r). Example 1: Find the greatest number that will divide 887 and 1061 leaving remainders 7 and 5 respectively. a) 32 b) 16 c) 176 d) 18 Solution: In the given example, a = 887, b = 1061, p = 7 and q = 5 a – p = 887 – 7 = 880 b – q = 1061 – 5 = 1056 Hence the required number = H.C.F. of 880 and 1056 which is equal to 176. Hence 176 is the greatest number that divides each of the numbers 887 and 1061 leaving remainders 7 and 5 respectively. Example 2: Find the greatest number that will divide 114, 148 and 182 leaving remainders 2, 4 and 6 respectively. a) 32 b) 16 c) 8 d) 28 Solution: In the given example, a = 887, b = 1061, p = 7 and q = 5 a – p = 114 – 2 = 112 b – q = 148 – 4 = 144 c – r = 182 – 6 = 176 Hence the required number = H.C.F. of 112, 144 and 176 which is equal to 16. Hence 16 is the greatest number that divides each of the numbers 114, 148 and 182 leaving remainders 2, 4 and 6 respectively. Thank You Ravi Raja

## Property 3:

Property 3: The least number which when divided by a, b, c leaves the same remainder ‘r’ in each case is {L.C.M. of a, b and c} + r. Example 1: Find the least number which when divided by 16, 18 and 20 leaves a remainder 1 in each case. a) 359 b) 361 c) 719 d) 721 Solution: In the given example, a = 16, b = 18, c = 20 and r = 1 L.C.M. of 16, 18 and 20 = 720 Hence the required number is 720 + 1 = 721. Example 2: Find the least number which when divided by 2, 3, 4, 5, 6, 7, 8, 9 and 10 leaves a remainder 1 in each case. a) 2159 b) 2561 c) 2519 d) 2521 Solution: The given property holds for any set of values of a, b and c. Hence in this example, the required number is {L.C.M. of 2, 3, 4, 5, 6, 7, 8, 9 and 10} + 1 = 2520 + 1 = 2521 Thank You Ravi Raja

## Property 4:

Property 4: The least number which when divided by each of a, b and c leaves remainders p, q and r respectively, such that a – p = b – q = c – r = k (say), is {L.C.M. of a, b and c} – k. (Note that in these type of problems, the remainders are such that the difference between the divisors and the remainders is the same in each case. This will become easier to understand once you go through the following two examples) Example 1: Find the least number which when divided by 7, 8, 9 and 10 leaves 5, 6, 7, and 8 as remainders respectively. a) 2518 b) 2522 c) 2528 d) None of these Solution: In the given example, a = 7, b = 8, c = 9, d = 10, p = 5, q = 6, r = 7, s = 8 and k = 2 Note that the difference between the divisors a, b, c, d and their respective remainders p, q, r and s is the same in each case and this difference = 2. Hence the required number is {L.C.M. of 7, 8, 9 and 10} – 2 = 2520 – 2 = 2518 Example 2: 20, 25, 30, 36 and 48 divides a number. The respective remainders obtained are found to be 15, 20, 25, 31 and 43. Find the least such number a) 3600 b) 3605 c) 3595 d) None of these Solution: Similar to the above question, note that the difference between the divisors and their respective remainders is the same in each case and this difference = 5. Hence the required number is {L.C.M. of 20, 25, 30, 36 and 48} – 5 = 3600 – 5 = 3595 Thank You Ravi Raja

## Thanks Ravi for explaining

Thanks Ravi for explaining everything in such a great detail with the properties

## Hi Ravisir thanks again for

Hi Ravisir thanks again for the solutions and answers I was checking your profile and you have mentioned your Occupation as Teacher but unfortunately you have not mentioned the location. If you are providing private tuition then please let the forum members know where you are located so that any body in that location can contact you

## Thank You so much

Thank You so much Anita and Thank You so much Palavi. I have posted one more solution of a problem and you can go through it: Here's the link: http://www.cat4mba.com/node/2107#comment-913 I might also need some help to visit posts on this site as I have no clue as to how to check the latest posts and all those things. Secondly I do not know as to how am I supposed to mention my location or else I definitely would have specified it. I went to the edit profile options but did not get to see anything that would make me give my location or make me give more details about myself. Anyway, I will try to find out something on my own and post more about myself. Thank You once again. Ravi Raja

## Few Tips on updating profile

For location Go to My account -> Edit Click on Personal tab to get the location field There are many ways to find the latest post but the best option is to check my profile Topics I've participated in: For Uploading Photos -> Go to create content ->Image and in Image Galleries choose my PICS for personal photos and choose other options depending upon the type of photo your uploading. All the photos you have uploaded‘ll be available in your profile Contact: If you enable it in my profile then all the registered members can send you personal mail w/o knowing your mail id.

## Thank You Nishit

Thank You so much Nishit. Actually I registered on Monday only and so I am new to this site and do not know much about it. Will try editing my profile accordingly as you have shown. For further help I will definitely come back to you. Thank You once again. Ravi Raja

## Solution to the Alcohol-water mixture question

Hi,

Guess this is the 1st solution I ve posted to this forum. The answer to the question is 20:43.

Explanation :

Let the the ratio of alcohol to water in the original mixture be m : n

So, let the actual quantities of  alcohol be mx , and water be nx, where x is some multiplication factor (which is actually immaterial as it eventually gets cancelled in our calculations).

So the total capacity is (m+n)x and 10% of the solution would be (m+n)x  / 10

Hence, our equation becomes,

mx - (mx / 10)                                             2

---------------------------------------      =        -----

nx - (nx / 10) + [ (m+n)x / 10 ]                    5

We can see that 'x' gets cancelled and on simplifying the above equation, we get m : n = 20 : 43

Regards,

Blazer !!