100 to 199 --- we have 20 numbers having 2 as a digit in them. 200 to 299 --- 120 numbers having 2 as a digit in them. 300 to 499 --- 20 . . . 700 to 799 --- 20 20 * 6 + 120 = 240
I guess. digit '2' has been used 20 times from 100 to 199, but total numbers being 19 because 122 entails two times 2. but it would be consider single time.
2)A and B are standing in a tunnel such that distance from the closer exit is 3/8 of the total lengthof the tunnel. They saw a train approaching the nearer end of the tunnel and they start movingtowards opposite ends with constant speed. Both just about managed to miss the train. If the speed ofthe train is 60 kmph what is the ratio of speed of A and B (speed of A & B are integers)?(a) 2:1(b) 3:1(c) 1:1(d) 4:1
_ _ _ x _ _ _ 1_____3/8d____P________5/8d______2
let train be x km away....when A and B are at point P
speed of A = A km/hr
speed of B = B km/hr
so...x/60 = 3/8d/A...(train and A meet at point 1)
and x+d/60 = 5/8d/B...(train and B meet at point 2)
put x = 45d/2A in 2 eqn
finally getting 45B + 2AB = 75A
ise kaise solve karna hai???...options se bhi nahi ho raha??..@Logrhythm
@joyjitpal -Suppose when they met, A covered D1 distance (D1=60T) and B covered D2 (D2=40T). Total dist = D1+D2 =100T. Now A has to cover D2 distance in some time say T'(D2=60T') and B has to cover D1 distance with 30km/hr,
(D1= 30(T'+2)). Just equate D1 and D2's , you get T as 1.5. hence,total distance = 100T =150
_ _ _ x _ _ _ 1_____3/8d____P________5/8d______2let train be x km away....when A and B are at point Pspeed of A = A km/hrspeed of B = B km/hrso...x/60 = 3/8d/A...(train and A meet at point 1)and x+d/60 = 5/8d/B...(train and B meet at point 2)put x = 45d/2A in 2 eqnfinally getting 45B + 2AB = 75Aise kaise solve karna hai???...options se bhi nahi ho raha??..@Logrhythm
bhai option voption choddo....iska ye tarika dekho karna ka...
X_ _ _ _ _ _a,b_ _ _ _Y
b travels 4 points in the time a travels 6 (point maan liya)
now when they meet speed of b reduces to 30 (half of a)...
a travels 4 points, so b will travel 2 points...
now b has to travel 4 points more...for which it is taking 2 hrs...
1)A & B are two trains start simultaneously from X & Y stations towards Y & X respectively withconstant speed 60 km/hr and 40 km/hr respectively. When they just crossed each other, speed of Bgot reduced to 3/4 th of its original speed,due to which B took 2 hours more than A to reach its destination.What is the distance between X and Y stations?a.200 kmb. 170 kmc. 150 kmd. 180 [email protected] @bs0409
original speed - A = 60 B = 40 reduced speed of B = 30
before meeting let distance covered by A & B = 60x and 40x
2)A and B are standing in a tunnel such that distance from the closer exit is 3/8 of the total lengthof the tunnel. They saw a train approaching the nearer end of the tunnel and they start movingtowards opposite ends with constant speed. Both just about managed to miss the train. If the speed ofthe train is 60 kmph what is the ratio of speed of A and B (speed of A & B are integers)?(a) 2:1(b) 3:1(c) 1:1(d) 4:1
bhai option voption choddo....iska ye tarika dekho karna ka...X_ _ _ _ _ _a,b_ _ _ _Yb travels 4 points in the time a travels 6 (point maan liya)now when they meet speed of b reduces to 30 (half of a)...a travels 4 points, so b will travel 2 points...now b has to travel 4 points more...for which it is taking 2 hrs...so 4points = 60 km..hence 10 points = 150km voila...
bhai option voption choddo....iska ye tarika dekho karna ka...X_ _ _ _ _ _a,b_ _ _ _Yb travels 4 points in the time a travels 6 (point maan liya)now when they meet speed of b reduces to 30 (half of a)...a travels 4 points, so b will travel 2 points...now b has to travel 4 points more...for which it is taking 2 hrs...so 4points = 60 km..hence 10 points = 150km voila...
bhai 2nd question ki baat kar raha hoon.(A:B ka ratio vala)..1st to hogaya..
_ _ _ x _ _ _ 1_____3/8d____P________5/8d______2let train be x km away....when A and B are at point Pspeed of A = A km/hrspeed of B = B km/hrso...x/60 = 3/8d/A...(train and A meet at point 1)and x+d/60 = 5/8d/B...(train and B meet at point 2)put x = 45d/2A in 2 eqnfinally getting 45B + 2AB = 75Aise kaise solve karna hai???...options se bhi nahi ho raha??..@Logrhythm
3)Sangeeta and Swati bought two wristwatches from Jamshedpur Electronics at 11.40 A.M. IST. After purchasing they found that when 60 minutes elapses on a correct clock (IST), Sangeeta's wristwatch registers 62 minutes whereas Swati's wristwatch registers 56 minutes. Later in the day Sangeeta's wristwatch reads 10 P.M., then the time on Swati's wristwatch is: a.8:40 PM b. 9:00 PM c. 9:20 d. 9:40 PM e. Cannot be calculated.
oh terri...dekha nahi...office mein hun yaar... for train wala...let us assume that the train is x km away from the near end...and also let the tunnel length be 8x/60 = 3/Va => x = 180/Va --- (1)(x+8)/60 = 5/Vbx+8 = 300/Vbx = 300/Vb - 8 --- (2)equate (1) and (2)180/Va = (300 - 8Vb)/VbVa/Vb = 180/(300 - 8Vb)abb kuch options daal kar ho jaye... pata nahi yaar dimaag nahi chal raha.. @mailtoankit
han ho jyga...
for making Va/Vb = 1:1
put Vb = 15...
but saala TSD kabhi seedhe tarike se nahi hota mujhse...galat baat hai..
3)Sangeeta and Swati bought two wristwatches from Jamshedpur Electronics at 11.40 A.M. IST.After purchasing they found that when 60 minutes elapses on a correct clock (IST), Sangeeta'swristwatch registers 62 minutes whereas Swati's wristwatch registers 56 minutes. Later in the daySangeeta's wristwatch reads 10 P.M., then the time on Swati's wristwatch is:a.8:40 PMb. 9:00 PMc. 9:20d. 9:40 PMe. Cannot be calculated.
bhai i dnt knw if this is a trick question but CBD hona chaiye...coz 10Pm of the same day nahi likha...10PM konse dinn ka...if same day ka hai toh aese nikaal lenge ki 1 hr mein 6 mins ka gap hai...
oh terri...dekha nahi...office mein hun yaar... for train wala...let us assume that the train is x km away from the near end...and also let the tunnel length be 8x/60 = 3/Va => x = 180/Va --- (1)(x+8)/60 = 5/Vbx+8 = 300/Vbx = 300/Vb - 8 --- (2)equate (1) and (2)180/Va = (300 - 8Vb)/VbVa/Vb = 180/(300 - 8Vb)abb kuch options daal kar ho jaye... pata nahi yaar dimaag nahi chal raha.. @mailtoankit
bhai i dnt knw if this is a trick question but CBD hona chaiye...coz 10Pm of the same day nahi likha...10PM konse dinn ka...if same day ka hai toh aese nikaal lenge ki 1 hr mein 6 mins ka gap hai...
@Logrhythm said:
bhai option voption choddo....iska ye tarika dekho karna ka...X_ _ _ _ _ _a,b_ _ _ _Yb travels 4 points in the time a travels 6 (point maan liya)now when they meet speed of b reduces to 30 (half of a)...a travels 4 points, so b will travel 2 points...now b has to travel 4 points more...for which it is taking 2 hrs...so 4points = 60 km..hence 10 points = 150km voila...@hiteshpratap said:
i think he was asking for tunnel vala question
thanks..
