Question
The speed of current is 10 km/h. What will be the
respective downstream speed and upstream speed of a boy rowing a boat, if one sixth of the distance covered going downstream in a certain time is equal to the distance covered going upstream in the same time?Solution
Let the speed of boy in still water be X km/h. And the speed of current = 10 km/h Downstream speed = (X + 10) km/h Upstream speed = (X – 10) km/h Let time be ‘t’ hours. ⇒ [(X + 10) t]/6 = (X – 10) t ⇒ X + 10 = 6X – 60 ⇒ X = 14 km/h Downstream speed = 14 + 10 = 24 km/h Upstream speed = 14 – 10 = 4 km/h
The ages of A, B and C together are 42 years. B is twice as old as A and C is 2 years older than A. What is the difference between ages of B and C?
P got married 8 years ago. His present age is 5/3 times his age at the time of his marriage. P’s sister was 10 years younger to him at the time of...
- The average age of 3 brothers is 24 years. If their ages are in the ratio 5:6:7, what is the age of the eldest brother?
The respective ages of a mother and her daughter are 30 and 8 years. In how many years will the mother be thrice as old as her daughter?
Mahesh said to his son, “At the time of your birth” I was as old as you are at present. If the Mahesh’s age is 42 years now then what will be the ...
- The current ages of R, S, and T are in the ratio 2:3:6. The difference between the ages of R and T is 40 years. After ‘m’ years, age of S will be 50% m...
The ratio of age of A and his son is 5:2. If the difference of their ages 5 years ago is 21, then find the sum of the ages of A and his son together 11 ...
The current age of Lisa is three times that of Maya. 5 years from now, Lisa's age will be twice the age of Tom at that time. If Maya is 3 years younger ...
The present age of A is 9/4 times to that of his marriage age. Present age of his brother is 1/3rd of his present age. If A was married 35 years ago the...
The ratio of age of ‘B’ after 5 years from now and age of ‘C’ 4 years ago from now is 7:4, respectively. The present age of ‘C’ is 30% of th...