Question
A boat can travel 30 km downstream in 45 min. The ratio
of the speed of the boat in still water to the speed of the stream is 5: 3. How much time will the boat take to cover 25 km upstream?Solution
Speed of downstream = D/T = 30 × (60/45) = 40 km/hr The ratio of the speed of the boat in still water to the speed of the stream = 5: 3 (5x, 3x) => 8x = 40 => x = 5 Speed of upstream = 5x – 3x = 2x = 10 km/hr Distance = 25 km Time = D/S = 25/10 = 2(1/2) hr = 2-hour 30 min
- Five years ago, the ratio of ages of 'X' and 'Y' was 2:3, respectively. Seven years from now, the ratio of their ages will be 4:5, respectively. If 'Z' is ...
The ages of A, B and C together are 54 years. B is twice as old as A and C is 6 years older than A. What is the difference between ages of B and C?
A girl’s age is 135% of what it was 10 years ago, but 75% of what it will be after 10 years. What is her present age?
Mohit is 4 years older than Nittu. The present age ratio of Nittu to Pawan is 11:6. Additionally, Mohit's current age is twice that of Pawan's. Based on...
18 years ago the average age of a family of four members was 45 years. Two children were born in that span of 18 years. The present average age of the f...
M and S currently have ages in the ratio of 3:4. R's present age is 50% more than S's present age. The ratio of M's age one year from now to R's age thr...
- 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 ratio of A and B present age is 7:3. The product of their ages is 8400. What will be the ratio of their ages after 4 years?
A lad was asked his age by his friend. The lad said “The number you get when you subtract 25 times my age from twice the square of my age will be thri...
- Four years ago, the ratio of ages of 'X' and 'Y' was 2:3 respectively. Six years from now, the ratio of their ages will become 4:5 respectively. If 'Z' is ...
