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Q:

What is the scientific name for washing soda?

A) Sodium carbonate	B) Sodium bicarbonate
C) Calcium carbonate	D) Calcium bicarbonate

Answer & Explanation Answer: A) Sodium carbonate

Explanation:

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Filed Under: General Science

Q:

Den Bosch and Eastbourne are two famous cities 300 km apart. Maradona starts from Den Bosch at 8:24 am . An hour later pele starts from Den Bosch. After travelling for 1 hour , Pele reaches Nottingham that Maradona had passed 40 minutes earlier. Nottingham falls on the way from Den Bosch to Eastbourne. If pele and Maradona just reaches Eastbourne at the same time, what are thespeeds of the Maradona and Pele Respectively?

A) 100 km/h , 125 km/h	B) 60 km/h , 80 km/h
C) 60 km/h , 75 km/h	D) 75 km/h , 100 km/h

Answer & Explanation Answer: D) 75 km/h , 100 km/h

Explanation:

Let Pele x km in 1 hour. so Maradona takes (2h-40min)=1 h 20 min to cover x km. Let speed of Maradona and Pele be M and P respectively than

x =M x (4/3) and x= P x 1

=> M/P = 3/4

Again $\frac{300}{M} = \frac{300}{P} = 1$

$\Rightarrow \frac{300}{3 k} - \frac{300}{4 k} = 1$

=> k= 25

M= 3k = 75 km/h and P= 4k = 100 km/h

( Through options it is very easy to solve)

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Filed Under: Time and Distance

Q:

Shahrukh starts from Barabanki to Fatehpur , 1 hour after Ajay starts. Shahrukh meets Kajol 1.5 hours after Shahrukh starts. If the speed of Shahrukh is at least 20km/h faster than the speed of Kajol.

What is the minimum speed of Shahrukh to overtake Ajay, before he meets Kajol?

A) 30	B) 40
C) 60	D) None of these

Answer & Explanation Answer: D) None of these

Explanation:

Let t be the time after Kajol starts, when she meets Ajay, then

t = 300/(x+y)

This should be less than 2.5 or (x+y)>120

Since y= 3x/2 => y > 72

This (y>72) is greater than 67.5 km/h and hence Shahrukh will always overtake Ajay before he meets Kajol.

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Filed Under: Time and Distance

Q:

A boat sails 15 km of a river towards upstream in 5 hours. How long will it take to cover the same distance downstream, if the speed of current is one-fourth the speed of the boat in still water:

A) 1.8h	B) 3h
C) 4h	D) 5h

Answer & Explanation Answer: B) 3h

Explanation:

Upstream speed = B-S

Downstream speed = B+s

B-S = 15/5 = 3 km/h

Again B= 4S

Therefore B-S = 3= 3S

=> S = 1 and B= 4 km/h

Therefore B+S = 5km/h

Therefore, Time during downstream = 15/5 = 3h

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Filed Under: Boats and Streams

Q:

Two horses start trotting towards each other, one from A to B and another from B to A. They cross each other after one hour and the first horse reaches B, 5/6 hour before the second horse reaches A. If the distance between A and B is 50 km. what is the speed of the slower horse?

A) 30 km/h	B) 15 km/h
C) 25 km/h	D) 20 km/h

Answer & Explanation Answer: D) 20 km/h

Explanation:

If the speed of the faster horse be $f_{s}$ and that of slower horse be $s_{s}$ then

$f_{s} + s_{s} = \frac{50}{1} = 50$

and $\frac{50}{s_{s}} - \frac{50}{f_{s}} = \frac{5}{6}$

Now, you can go through options.

The speed of slower horse is 20km/h

Since, 20+30=50

and $\frac{50}{20} - \frac{50}{30} = \frac{5}{6}$

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Filed Under: Time and Distance

Q:

If Deepesh had walked 20 km/h faster he woulh have saved 1 hour in the distance of 60km. what is the usual speed of Deepesh?

A) 100	B) 120
C) 150	D) None of these

Answer & Explanation Answer: A) 100

Explanation:

Let the original speed be x km/h, then

$\frac{600}{x} - \frac{600}{(x + 20)} = 1$

$\Rightarrow 600 (\frac{x + 20 - x}{x (x + 20)}) = 1$

$\Rightarrow x^{2} + 120 x - 12000 = 0$

$\Rightarrow (x - 120) (x - 100) = 0$

Therefore, original speed = 100km/h

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Filed Under: Time and Distance

Q:

A Person X started at 3 hours earlier at 40km/h from a place P, then another person Y followed him at 60km/h. Started his journey at 3 O'clock, afternoon. What is the diference in time when X was30 km ahead of Y and when Y was 30 km ahead of X?

A) 2h	B) 3h
C) 3.5h	D) 4.25h

Answer & Explanation Answer: B) 3h

Explanation:

Time ( when X was 30 km ahead of Y) = (120-30)/20 =4.5h

Time ( when Y was 30 km ahead of X) = (120+30)/20 = 7.5 h

Thus, required difference in time = 3h

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Filed Under: Time and Distance

Q:

A person goes to his office at 1/3rd of the speed at which he returns from his office. If the average speed during the whole trip is 12 m /h . what is the speed of the person while he was going to his office?

A) 10	B) 6
C) 8	D) can't be determined

Answer & Explanation Answer: C) 8

Explanation:

u = k , v= 3k

$∴ \frac{2 u v}{u + v} \Rightarrow \frac{2 \times k \times 3 k}{(k + 3 k)} = 12$ => k = 8km/h

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Filed Under: Time and Distance

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