REVISION CLASSES FOR PRELIMS 2017 by **Forum**IAS

ForumIAS will be conducting revision classes for Prelims 2017. The goal is to cover maximum topics in minimum time posible. The first class is scheduled __today__ at 5 PM. Seats fill early so register early. Click Here to know more

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## Comments

a and b are able to finish work in 8 days so they will finish half work in 4 days.rest of 1/2 work which would done by b and c.b works for 2 additional days so b does 2/12=1/6 work in two days.remaking work left=1/2-1/6=1/3 which will done by c in 4 days as 12/3=4

seems different from other aptitude exams. I have sarvesh Varma quantum cat book and ncerts. Would this suffice? I find Quant questions on the higher side of difficulty level.

Am planning to do these exclusive topics 2 weeks before pre and a month before cgl mains.

Which is the best book for numerical aptitude?

Therefore (A+B)'s work in 1 day will be = 24/8 = 3 units

B and C alone complete work in 12 days.

Therefore B and C both alone do 24/12 =2 units in 1 day.

A's alone 1 day work= (A+B)-B = 3-2 =1

Therefore A and B together complete in 4 days = 4 x 3 = 12 units

remaining work= 24-12 = 12 units

B alone works for next two days = 2x2 = 4 units of work

remaining work = 12-4 = 8 units

C completes 2units of work in 1 day

therefore, he will complete 8 units of work in = 8/2 = 4days

Therefore answer is 4days

PS. We usually do it in short but for ur understanding i elaborated each step

If you put x= 0, then then we will get 18. If you put x= 10, then you will get 8. However, if you put a number x between 2 and 9, it will generate negative answer. So one number less than 9 i.e. 8. If we put x=8, then we will get the value as (8-2)(8-9) = -6. This can be the least value formed

C.P of 1st batch 4 10

CP of 2nd batch 5 10

SP of both batch 9 20

Taking LCM of articles as 180 we can solve this problem. Let total articles in first batch be 180

Now, in the first batch, each bundle is of 4 articles...so total bundle = 180/4 = 45 bundles

Therefore the price of all 180 articles will be Rs 10 x 45 bundles = Rs 450

Similarly, in 2nd batch, there will be 180/5= 36 bundles and total price will be = 36 x10= Rs 360

Adding both the batches, the total cost price= 450+360= Rs810

Now coming on to Selling Price

Since, there are two batches, therefore total articles sold = 180+180 =360 articles

each batch is of 9 articles, so total batches sold = 360/9= 40 batches

Selling Price of each batch is Rs 20, so selling price of all batches will be= Rs 20 x 40 batches = Rs 800

Clearly SP<CP, therefore, it is loss.

You can easily calculate it:

loss %= (C.P.-S.P)/C.P x100= (10/810) x 100 = 100/81% = 1 19/81 % loss

therefore price of black pair = Rs20

Let number of brown and black socks be respectively x and y

thus original transaction = 10x+20y

new transaction by error = 10y+20x

As per the question, the bill is increased by 50%. Therefore new price will be 150% of the original one

new transaction= 150% of original

10y+20x= 150% of (10x+20y)

y+2x= 3/2 (x+2y)

2y+4x=3x+6y

4x-3x=6y-2y

x=4y

y/x=1/4

y:x=1:4

i.e. number of black socks : number of brown socks= 1:4 <-- answer

other way of solving-

since equal no. of oranges are brought so take LCM of 4,5 = 20

=> 20 oranges for 50 rs

& 20 oranges for 40 rs.

so CP of 40 oranges= 90 rs => CP of 1 orange=9/4

a/q SP of 1 orange = 20/9

so LOSS (9/4>20/9) = (100/81) %