Q:

A takes 24 day in completing a work alone. Time taken by A in completing 1/3rd of the work is equal to the time taken by B in completing half of the work. How many days will be taken in completing the work if both A & B start working together?

A) 21/3 days B) 48 days
C) 40 days D) 48/5 days
 
Answer & Explanation Answer: D) 48/5 days

Explanation:

Ans. 
Time taken by A to complete a work alone - 24 days
Time taken by A in completing 1/3 of work = 24*1/3= 8 Days
8 day = time taken by B in completing 1/2 of work
B alone can complete the work = 16 days
The required time in completing the work if both A & B start working together?
16*24 / 40 = 48/5 Days

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Filed Under: Time and Work
Exam Prep: AIEEE , Bank Exams , GATE

2 2854
Q:

A train left from station A for station B at 4 pm at an average speed of 80 kmph. At 8 pm, another train also had left from station A for station B on a parallel track at an average speed of 120 kmph. How far from A is another train expected to overtake the first train?

A) 900km B) 940km
C) 960km D) 980km
 
Answer & Explanation Answer: C) 960km

Explanation:

Ans. 
Distance covered by 1st train in 4 hours = 80*4 = 320 km
Relative speed of 2nd train = 120-80 = 40 km
It will overtake another train in 320/40 = 8 hours
Distance between overtake point and station A = 8*120 = 960 km

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1 2950
Q:

In a business, A invested 1200 rs. more than B. B invested his amount for 15 months while A invested for 4 months more than that of B. If total profit was 1240 rs. in which the profit of B is 280 Rs. less than that if A. then what was the invested amount of A?

A) 6000 B) 7000
C) 5000 D) 8000
 
Answer & Explanation Answer: A) 6000

Explanation:

Ans. 
Let B’s investment = x rs.
∴ A’s investment =( x + 1200) rs.
Ratio of the profits of A and B = (x+1200)*(15+4):x*15 = {19(x+1200)}:15x
Now,let the total profit of A =y
∴ total profit of B = (y-280)
But total profit = 1240
⇒y+(y-280)=1240
⇒2y=1520
⇒y= 760
∴profit of A = 760rs.
Profit of B = 760-280=480 rs.
Ratio of profits= 760:480 = 19:12
According to the question,

19(x+1200)/15x = 19/12

12x+14400 = 15x

⇒3x = 14400
⇒x = 4800 rs.
⇒investment of A = 4800+1200
                          = 6000 rs.

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Filed Under: Profit and Loss
Exam Prep: AIEEE , Bank Exams , GATE

3 3570
Q:

The ratio of volume of a cone to that of a cylinder if cylinder radius is reduced by 4 times and its height increased by 8 times of that of the cone, is - 

A) 3:2 B) 2:3
C) 5:7 D) 7:5
 
Answer & Explanation Answer: B) 2:3

Explanation:

Ans. Let radius of the base and height of the cone be ‘r’ & ‘h’ respectively.

Then volume of cone = πr2h/3 For cylinder, radius is reduced by 4 times = r/4 And,  height is increased by 8 folds = 8h Volume of cylinder = πR2H = π(r/4)2 (8h) = (16/8)πr2h = πr2h/2 Ratio of volume of cone to volume of cylinder = (πr2h/3) : (πr2h/2) Or, Ratio = 2 : 3.

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1 1712
Q:

The speed of a boat when travelling downstream is 32 km/h, whereas when travelling upstream it is 28 km/h. What is the speed of the boat in still water?

A) 27 km/h B) 29 km/h
C) 31 km/h D) Cannot be determined
 
Answer & Explanation Answer:

Explanation:

Ans.  Suppose the speed of boat in still water is x km/h and speed of stream is y km/h

Speedof boat in downstream = (x + y) km/h x+ y = 32 …(i) 

Speed of boat in upstream = (x – y) km/h

x – y = 28 …(ii)

Add. Eqs. (i) and (ii), we get 2x = 60

x = 30 km/h

 

 

 

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0 1691
Q:

A shopkeeper mixed two verities of rice at Rs. 40/kg and Rs.60/kg in the ratio 3: 2 and sold the mixture at 10% profit. Find the  price per kg at which he sold the mixture?

A) Rs. 56 B) Rs. 58.8
C) Rs. 54 D) Rs. 52.8
 
Answer & Explanation Answer: D) Rs. 52.8

Explanation:

Ans.  CP of mixture = {(40*3+60*2)/2+3} = 48 SP of the mixture = 1.1 48 =52.8

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0 1383
Q:

Four statements are given below at A, B, C and D. There may be some errors in the given statement(s). The incorrect statement is your answer.

 

A) To drain water away from the tracks, railroad beds, like road beds, are designed in which there is usually a bed of rock and gravel resulting in fast drainage from the tracks. B) Railroad beds, like road beds, are designed in which there is usually a bed of rock and gravel that results in the fast drainage from the tracks.
C) A bed of rock and gravel, called the railroad bed, is designed similar to a road bed to drain water away from the tracks. D) Railroad beds, like road beds, are designed to drain water apart from the tracks, so there is usually a bed of rock and gravel resulting in fast drainage away from the tracks.
 
Answer & Explanation Answer: D) Railroad beds, like road beds, are designed to drain water apart from the tracks, so there is usually a bed of rock and gravel resulting in fast drainage away from the tracks.

Explanation:

‘apart’ is incorrect after ‘to drain water’

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0 939
Q:

Four statements are given below at A, B, C and D. There may be some errors in the given statement(s). The incorrect statement is your answer.

A) Many Japanese cities had extensive tram systems until the 1960s, when increased motorization started to make some lines disappear. B) Increased motorization started to make some lines disappear after the1960s until when many Japanese cities had extensive tram systems.
C) When increased motorization started to make lines disappear, many Japanese cities have extensive tram systems until the 1960s. D) Until the 1960s, when increased motorization started to make some lines disappear, many Japanese cities had extensive tram systems.
 
Answer & Explanation Answer: C) When increased motorization started to make lines disappear, many Japanese cities have extensive tram systems until the 1960s.

Explanation:

‘has’ is incorrectly used since the sentence is in past tense. Moreover, the subject is cities, which is plural.

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0 913