Question
The speed ratio of a stream to the upstream speed of a
boat is 1:9. A boat takes 2 hours and 30 minutes to travel 82.5 km downstream. Determine the time (in minutes) the boat will take to travel 54 km in still water.Solution
Let the speed of boat in still water and speed of stream be 'v' and 'x' km/h respectively. ATQ, x:(v - x) = 1:9 Or, 9x = v - x Or, 'v' = 10x -------- (I) Downstream speed = v + x = 10x + x = '11x' km/h So, 11x = (82.5/2.5) Or, 11x = 33 So, 'x' = 3 On putting value of 'x' in equation (I) , We get, 'v' = 10 X 3 = 30 Therefore, required time = (54/30) = 1.8 hours = 1.8 X 60 = 108 minutes
- A girl appeared in 5 exams, each having a maximum of 200 marks. Her scores in the exams were 180, 150, 165, 190, and 175. She randomly tells her marks of o...
A bag contains 19 white and some black balls. If the probability of drawing a black ball from the bag is twice that of drawing a white ball, find the nu...
- A basket contains x black balls, (x + 3) white balls and (x + 6) yellow balls. If probability of picking a white ball is 1/11 more than that of picking a b...
Tokens numbered 1 to 350 are in a bag. What is the probability that the Token drawn has a number which is a multiple of 6 or 7?
There are (m + 6) red roses, (m + 12) white roses and ‘m’ pink roses in a bag. If the probability of picking a pink rose is 4/15, then find the valu...
A bag contains 7 (one rupee coins), 4 (two rupee coin) and 5 (ten rupee coin). Find the probability that 3 coins drawn at random are either (two rupee c...
In a cricket world cup the probability that India will win the cup is ¼. The Probability of Pakistan winning the cup is 1/5 and Australia winning the c...
A bag contains 5 red flowers, 7 yellow flowers and 8 green flowers. 3 flowers are drawn randomly. What is the probability that the flowers drawn contain...
There are (m + 4) red roses, (m + 11) white roses and ‘m’ pink roses in a bag. If the probability of picking a pink rose is 5/16, then find the valu...
A bag contains 12 white and some black balls. If the probability of drawing a black ball from the bag is thrice that of drawing a white ball, fin...