Three bells toll at intervals of 9, 12, 15 minutes respectively. If they start tolling together, after what time they next toll together?
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There is a circular path around a sports field. Preeti takes 18 minutes to drive one round of the field, while Suman takes 12 minutes for the same. .
Solution: They will be meet again after LCM of both values at the starting point. To get the LCM we have to factorize the number. 18 = 2 × 3 × 3 12...
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A trolley, while going down an inclined plane, has an acceleration of 2 cm/s^2 . What will be its velocity 3 s after the start?
Here we have, Initial velocity, u = 0 m/s Acceleration (a) = 2 cm/s2 = 0.02 m/s2 Time (t) = 3 s Final velocity, v = ? We know that, v = u + at Therefore,...
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A racing car has a uniform acceleration of 4 m/s^2 . What distance will it cover in 10 s after start?
Here we have, Acceleration, a = 4 m/s2 Initial velocity, u = 0 m/s Time, t = 10 s Distance covered (s) =? We know that, s = ut + 1 /2 at2 ⇒ s =...
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On morning walk, three persons step off together and their steps measure 40 cm, 42 cm and 45 cm, respectively.
Solution: Since, the three persons start walking together. Therefore, The minimum distance covered by each of them in complete steps = LCM of the measures of their steps = LCM (40, 42, 45) 40...
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For a morning walk, three persons steps off together. Their steps measure 80 cm, 85 cm and 90 cm respectively.
Solution: Since, the three persons start walking together. Therefore, The minimum distance covered by each of them in complete steps = LCM of the measures of their steps = LCM (80, 85, 90) 80...
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Three consecutive integers are such that when they are taken in increasing order and multiplied by 2, 3 and 4 respectively, they add up to 74.
Let the three consecutive integers be x, x+1and x+2. According to the question, 2x+3(x+1)+4(x+2)=74 => 2x+3x+3+4x+8=74 => 9x+11=74 =>9x+11-11=74-11 [Subtracting 11fromboth sides] => 9x=63 => 9x/9=63/9 [Dividing both sides by9] => x=7 Hence first integer = 7, second integer=7...
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A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:
(ii) 25 km------------------- Solution: Case I: Speed = 40 km/h Time = 15 min = 15/60 hour Distance = Speed × Time = 40×15/60=10 km Case II: Speed = 60 km/h Time = 15 min = 15/60 hour Distance...
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A person travelling on a straight line moves with a uniform velocity v_1 for some time and with uniform velocity v_2 for the next equal time.
(a) v = (v1 + v2)/2. Explanation: Let t be the time related to each velocity. Total distance travelled =v1t+v2t. Total time taken=2t. Hence average velocity = v1t+v2t/2t =(v1+v2)/2.
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Three girls start jogging from the same point around a circular track and they complete one round in 24 seconds,
(b) Required time = L.C.M of 24, 36 and 48 = 144 seconds = 2 minutes 24 seconds
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Three friends A, B and C start running around a circular stadium and complete a single round in 24, 36 and 30 seconds respectively.
(b) Required time = L.C.M of 24, 36 and 30 = 360 seconds = 6 minutes
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