Question
A boat moves in a river where the ratio of the speed of
the stream to the downstream speed of the boat is 1:6. If it takes the boat a total of 20 hours to travel 144 km downstream and return 144 km upstream, how much time will it take to cover 180 km in still water?Solution
ATQ,
Let the downstream speed of a boat and the speed of stream be 6x km/hr and 'x' km/hr respectively.
Or, upstream speed of boat = 6x - x - x = 4x km/hr
ATQ,
(144/6x) + (144/4x) = 20
Or, (24/x) + (36/x) = 20
Or, (60/x) = 20
So, 'x' = 3
So, speed of boat in still water = 6x - x = 5x = 5 × 3 = 15 km/hr
So, required time = (180/15) = 12 hours
A mixture contains ‘x’% milk. 30% of this mixture is taken out and is replaced with same quantity of water. This procedure is repeated two more time...
A container contains Alcohol and water in ratio of 3:5 and Capacity of Container is 160 lit. If half of the Container is replaced with 40 lit of water t...
Two mixtures A and B are in the ratio of 3:2. Mixture A contains ×% of milk and a% of water. Mixture B contains y% of milk and b% of water. If mixture ...
A trader mixes two kinds of wheat of 8 kg and 2 kg, costing Rs. 3 and Rs. 9 per kg, respectively. What is the cost price (in Rs.) of the mixture per kg?
150 litres of Mixture ‘A’ (water + alcohol) contains 32% water and remaining alcohol while 112 litres of mixture ‘B’ (milk + water) contains 20 ...
A jar contains a mixture of milk and water in the ratio 2:3, respectively. If 3-litres of the mixture is taken out, then the quantity of water left in t...
A mixture of milk and water contains 25% water. On adding 20 litres of water, the quantity of milk becomes 40% more than that of water. Find the initial...
Quantity of milk is 20% more than that of water in 220 litres mixture (milk + water). If 22 litres milk is added, then find the quantity of milk in the ...
- An alloy consists of 35% gold, 40% silver, and 25% copper. How much gold should be added to 20 kg of the alloy so that the new alloy contains 50% gold?
Quantity of water in a 300 litres mixture (alcohol + water) is 40 litres less than the quantity of alcohol in it. Find the quantity of water to be mixed...
Relevant for Exams:
