Question
The downstream speed of a boat is
25% more than its upstream speed. The boat takes 3.2 hours to travel 57.6 km upstream. Which of the following statement(s) is or are true according to the information? I. Speed of stream is 3 km/h II. Time required to cover 108 km in still water is 4 hours III. Time needed to go 72 km downstream and return upstream is 7.2 hoursSolution
ATQ: Upstream speed = 57.6 / 3.2 = 18 km/h Downstream speed = (5/4) × 18 = 22.5 km/h Statement I: Speed of stream = (1/2) × (22.5 − 18) = 2.25 km/h → ❌ False Statement II: Speed in still water = (1/2) × (22.5 + 18) = 20.25 km/h Time = 108 / 20.25 ≈ 5.33 hours → ❌ False Statement III: Time = (72 / 22.5) + (72 / 18) = 3.2 + 4 = 7.2 hours → ✅ True ✅ Only statement III is true
A chemist combines three solutions with active ingredient concentrations of 10%, 20%, and 30% in the ratio 2:3:5. If the total volume of the mixture is ...
The number of boys and girls in a school is 140 and 250 respectively. 30% of boys left the school while 30 girls took admission in the school. Find the ...
- Three values P, Q, and R are such that P is one-third of Q and R is the average of P and Q. If the total of all three values is 588, find the second larges...
Reema’s income in March was four times what she earned in each of the other months of the year. What is the ratio of her income in March to her total ...
If ₹19,500 is divided among ‘A’, ‘B’, ‘C’, and ‘D’ in the ratio 6:8:5:7, then find the share of ‘C’.
...If the base radius of 2 cylinders are in the ratio 3 : 4 and their heights are in the ratio 4 : 9, then the ratio of their volumes is:
- Ratio of number of boys to girls in a school of 840 students is 5:3. Ratio of number of boys who passed to those who failed in an exam is 11:4 whereas rati...
- Rs. 42000 is divided among 'Aman', 'Bhanu' and 'Chirag' in such a way such that amount received by 'Aman' is (7/10) of amount received by 'Bhanu' and (7/4)...
Rs. 960 is divided among A, B and C in the ratio 4 : 5 : 7. What is C’s share?
Relevant for Exams:
