@ace100percent said: Brass is an alloy of copper and zinc. Bronze is an alloy containing 80% copper, 4% zinc, and 16% tin. A fused mass of brass and bronze is found to contain 74% of copper, 16 % of zinc, and 10% of tin. The ratio of copper to zinc in Brass is :( pg number 246 q no 10 arun sharma) friends please give me the detailed solution for this q
see i did it. but in a very long way
lets say we have bronze 100 grams. so we have 80g Cu , 4g Zn and 16g of Sn (Tin) lol.
so now in mixture we have 10% tin. it will be possible only when we have a mixture of 160g ( 100g bronze and 60g brass) . sinze brass has no tin in it.
now tin part is sorted out. we have 74% of 160g copper. and 16% of zinc. since we know that we added 100g of bronze. we can calculate amount of copper and zinc in 60g of brass and then find out the percentage. i hope it helps.
lets say we have bronze 100 grams. so we have 80g Cu , 4g Zn and 16g of Sn (Tin) lol.
so now in mixture we have 10% tin. it will be possible only when we have a mixture of 160g ( 100g bronze and 60g brass) . sinze brass has no tin in it.
now tin part is sorted out. we have 74% of 160g copper. and 16% of zinc. since we know that we added 100g of bronze. we can calculate amount of copper and zinc in 60g of brass and then find out the percentage. i hope it helps.
Can someone give a shorter solution?
The Tin has come in the alloy has come only from the bronze i.e 10% from the 16% in bronze. LCM of 10 and 16 = 80 so let the weight of the alloy be 800 grams. (easy for calculation)
copper is = 74/100*800 = 592 grams Zinc = 16*8 = 128 grams Tin = 10* 8 = 80 grams.
From the bronze we will find the contribution of each metal - Tin = 16 * 5 = 80 grams Copper = 80* 5 = 400 grams Zinc = 4*5 = 20 grams.
The residue has come from Brass: - Copper = 592 - 400 = 192 grams Zinc = 128 - 20 = 108 Grams
@crazy4pagal said:7 white balls & 3 black balls are randomly placed in a row. Find the probabilitythat no two black balls are placed adjacent to each other??For this question after counting the total no. of possible arrangements i.e 120. What I did was clubbed two balls together and counted the no. of arrangements which I thought should have given the right answer but alas! NO.I understand the other way of arranging the white balls in a row and selecting 3 out of 8 empty spaces i.e 8C3/120 which is the required probability but what was the problem in my approach.i did 10!/3!7! - 9!/2!7! .Any1 ??
total nos of ways - 10!/7! *3! = 120.. ways of arranging so that no 2 black balls are together:- 1st arrange the 7 white balls and so 8 gaps will be created..no 3 black balls can be arranged in 8c3 ways = 56.. prob = 56/120..
@saikatdgp u r awesome!! i know, faaltu me i complicated it...wen we have a simpler approach. thanx newaz...hey!! can u help me solving an quadratic inequality within modulus. Like | ( x^2 - 3x - 1 ) / ( x^2 + x + 1 ) | ?? Please paste the approach. Thanx again...
can sum1 help me solving an quadratic inequality within modulus. Like | ( x^2 - 3x - 1 ) / ( x^2 + x + 1 ) | ?? I mean just the approach, confused !! If we open the mod by taking the value within mods to be greater than zero, and get some range. And now we solve for 'x' , so do we take the union of both the solutions i.e for which x>0 and the inequality solution. Looks ideal to me, but the solution doesn't say that...ANy1 please??
@pandeyn Assume the speeds to be anything, let us say...30kmph and 40 kmph. Now, X has a head start of 140 m, so that leaves to a case where Y has to cover 500 kmph whereas X is left with 360. At a speed of 30, it'll take 12 hrs to cover that distance for X. Clearly, in 12 hrs. Y will cover 480 kms. So the answer is 20 km.
However, if u r wondering how could we assume speeds. Then, it wont matter here as we are required to calculate the distance which is a constant here. Hope, it helps.
@UnCharismatic For some chapters, its unnecessary really...but required in some chapters for sure. My suggestion, do LOD 1 and LOD 2 and then go for solving PG Prep, TG ebooks, and mocks...
@crazy4pagal said: Hey all!! m almost over with Arun SHarma...suggest me some other good book with lesser mistakes, diverse set f problems and correct solutions??
Is it not enough to go with Arun Sharma completed? I am asking as I have started preparation 1-2 weeks back only and i am not left with too much of time.
@pandeyn Sorry bro!! the book is full of redundant questions...No need to worry, basics are good in the book, solve it first...but go for a good mock test series at least...PG prep is always there...
i have completed quant by arun sharma but still not able to solve question with good accuracy..i have heard a lot about TIME test series..but i dnt think that there's time now..so can someone plz recommend me any mock test series that i can give sitting at home..i dnt have any clue about all this..plz help..TIA :)
I was checking one question on area of cone in Arun sharma , cam e to know about a nee formula : (1/3) *pi* r^2*h , was wondering how that is possible question number 11.1 a page number 356
