Difference Between SI and CI Problems

This is very small concept and also important to remember. Check the following Image to solve the Difference between SI and CI - Problems.

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Difference between SI and CI

I found this Video useful and hence placing this here.. Watch it and learn. If you are unable to find the video please Click Here.

Prepare well for SBI PO.

Time and work (method - 2)

 We solve time and work problems also by using time and efficiency. So now, we see hoe to solve in this method.

               

	A	B
Time T
Efficiency E

The table is the basic rule. Now when we fill the columns in table, Ta * Ea  = Tb * Eb

ie., efficiency should be appropriate. Here Efficiency is nothing but the ratio in reverse order.

Efficiencies should be noted in reverse order..  of ratios.

If Ratios of A and B are 2:3, then efficiencies must be.. 3:2… Now Ea=3 and Eb=2

Now,  work done is..W = T x E (of  either A or B, as both are same)

Work done by A = W/Ea                 ;(Ea=Efficiency of A)

Work done by B = W/Eb                  ; (Eb=Efficiency of B)

Work done by A+B = W/E(a+b)     ; (Ea+b=Sum of Efficiencies of A and B)

Example:

A can do a work in 10 days. B can complete the same work in 20 days. If they work together, how many days they take to complete.

Ans : 6 2/3 days

Solution:

    A   B

T  10 20                                                                                                 w = 20

E   2   1 (as Ratio of A and B but in reverse order…)            Wa+b = 20/3 = 6 2/3 days…

 Refer Method - 1 here..

Time, Distance and Train Problems

This is the major topic in any competitive examinations. So, I am now explaining the shortcut and the fastest method for solving these problems. There are four different types of problems in this topic.
They are:          1. Problems on Time taken by train

2. Problems on Distance covered by train

3. Problems on speed of train

4. Problems on 2 trains in same direction

5. Problems on 2 trains in opposite direction

6. Problems on finding Length of train or platform

7. Problems on platform crossing time

8. Average speeds

  You all know this basic Triangle.

/\

/  D \

/ T |  S \

D – Distance , T – Time,  S – Speed , L – length of train, Lp – Platform length

 Where d=t *s

                T= d/s

                S= d/t

Time calculated when distance and speed is given          :               t=d/s

                                When length (l) and speed is given         :        t= l/s      (pole/man crossing time)

Time taken to cross platform     :               (L+Lp)/s

Relative speeds                               : Same direction = (S1 – S2)         ; (where s1 >s2)

                                                : Opposite direction = (S1+S2)

Time taken by trains cross in same direction is (sum of lengths of trains / diff in speeds)

Time at which 2 trains pass by is (Sum of lengths / sum of speeds)

Important NOTE:

Conversions:                     18 kmph = 5mps

                10 mts --->1kmph ---> 36 sec

                                20 mts ---> 2kmph ---> 36 sec

                                30 mts ---> 3kmph ---> 36 sec and so on..

Ie, a vehicle travels 10 meters distance with 1kmph speed in 36 seconds

Vehicle travels 20 meters distance with 2kmph speed in 36 seconds

Vehicle travels 30 meters distance with 3kmph speed in 36 seconds

Vehicle travels 40 meters distance with 4kmph speed in 36 seconds and so on..

Now, we will see how to use the above shortcut.

A car travels with a speed of 108kmph. What distance will be covered in 15 sec?

Ans : 450mts

Solution: Write the given parameters in above format

1080mts --> 108 kmph ---> 36sec

Now we know distance travelled in 36 sec. Find 15sec distance using this.

Ie by Ratio method as i already mentioned in my previous posts Ratio and Proportion

                36 --> 1080

                15 --> ??                (450)

Average speeds:

When distance is constant ie speeds are given  :               2ab/ (a+b)

When distances and times are given                  :               Total distance/ Total time

Try some problems and Answer them:

                         

1.90kmph in m/s

2.52m/s in kmph

3.A vehicle covers a distance of 600mts in 2 mins. What is Speed in kmph

4.A car runs at 78kmph. What is the distance covered in 1min 12 sec?

5.At what time car travels over a distance of 420mts, if it runs at 90kmph?

6.The ratio between two trains’ speeds is 7:8. If second train runs 400kmph in 5hrs, the speed of first train is?

7.Speeds of A and B are in ration 3:4. A takes 20 mins more than B to reach the destination. Then What is time taken by A and B to reach the destination?

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NICL AAO – (Generalist) 15th December, 2013 morning session

Quants

1.       No. of units in computer CPU – three     (As we need to mark answers with Ball point pen, I marked this wrongly. I marked it as five..  )

2.           

3.       A’s age is 4 less than the twice of his brother. (not remembered )

4.       In a triangle RST, RS .|. TS, angle R is 40 degrees. If a point is placed on RT which forms a 100degrees angle (ie angle SWR is 100degrees) then which line is the shortest of all. - WR

5.       When a person travels with 3kmph, he is late by 15mins. And when he travels with 4kmph, he is early by 15 mins. Find the actual distance.  Options – 12/6/7.2kmps etc

6.       A tap fills a tank in 5hrs and other tap when opens, empties the same tank in 4hrs. total time taken to fill the tank is – 20hrs

7.       Cost of 8chairs is equal to 2tables. Cost of 12chairs and 2tables is `4000. Find 10chairs and 1 table cost - `2800

8.       A student  asked to divide a number by 6 and add 12 to its quotient. Instead he added 12 to the number and then divided it by 6 obtaining a value 12. Find number- 122

9.       A man bought 3 eggs for 5rs. And sold 5 for 12rs. If he get 148 rupees how many eggs he sold.

10.   Avg. of a,b,c,d is p. Avg of a,c is q. now what is b+d in terms of p and q ? =(2p-q)

11.   On a marked price of rs.275, shopkeeper gives a discount of 5%. And if he gains a profit of 4.5%, what is the Cost price?

12.   There are blue, green, red balls in a bag. Probability of getting blue ball is 0.25 and probability of red ball is 0.40. What is the probability of getting green? – 0.35

13.   1/8 of 2/3 of 4/5 of number is 12. 30%of number is –

14.   Zinc and copper is in ration 5:3 in 200gms. How much zinc is to be added to get the ratio 3:7?

15.   (not actually remembered this) A circular with radius 88mm is laid around 2mts circle. Find the area of circular path.

16.   Reciprocal factors of ax^2 +bx+c=0.

17.   Which of the following cannot be used as the equal angles for a polygon? – (I think its 162, options are 160 162 140 etc)

Reasoning :

1.       Find Exact reflection image

2.       If A is facing west. Then he Turned 45deg clockwise. Then 18odeg clock wise and then 270 in anti-clockwise direction. Now position of A is..

3.       A is south-west of B. C is south East ofB. Position of C wrt A.

4.       Oddman out – meal – jail - bait – fail

5.       If KILL is coded as 7133 and SNACK is coded as 25847. 58132 is – NAILS

6.       If BOAT is     ACNPZBSU then, TEST is --  SUDFRTSU

7.       Illiterate: Education ::

8.       Consecrate : Desecrate :: -- agree : disagree

9.       Questions on NON VERBAL – 2

10.   Questions on ANOLOGY – 4

11.   Questions on SERIES – 3 (vowel followed by or number preceded by )

GENERAL AWARENESS

1.       ASCII –

2.       RBC (red blood corpuscles ) are produced in – bone marrow

3.       Hypertext is introduced by –

4.       Larger importer of world is – USA / china / Brazil / Germany

5.       Very rigid and hard bonds in carbon alloy is – Diamond

6.       (most of them are standard gk.. inventions etc )

1.        asked about related persons..

2.       Which country is 3rd largest market for TWITTER?

3.       India 2020 is written by?

4.       In union budget 2013-14, duty on cigarette is increased to?

5.       To whom Doctrine of lapse is related?

6.       Where Depotism is possible?( Options - One party state/ two party state/ two party state/ two n more)

7.       Varahamihira wrote a book “brihad samhita”, it is related with (options – finance, science etc )

8.       In whose period, painting got full famous : Jahangir

9.       Who is called Nepolian of india: samudragupta

10.   Logo of WWF- panda (options panda, red panda, tiger)

Descriptive: 3 questions

1.       Comprehension and questions – 20marks – 5 questions

2.       Essay – Caste system and its effect on Indian Politics (I Actually don’t know what to write on this)

3.       Presis writing – given a big paragraph about Gandhiji. (Don’t think that was easy.. still far better than Essay)