৬৭৩১
The speed of a boat in still water is 6 km/h. The time it takes to travel downstream is half the time it takes to travel upstream. What is the speed of the stream?
উত্তর
2 km/h
৬৭৩২
A grocer mixes two types of pulses, one costing 15 taka per kg and the other 20 taka per kg. If the mixture is sold at 16.50 Taka per kg, what is the ratio of the two types of pulses in the mixture?
উত্তর
7 : 3
৬৭৩৩
A swimmer swims in a river against the current and takes 30 minutes to swim 2 km. With the current, he takes 20 minutes to swim the same distance. What is his speed in still water?
উত্তর
5 km/h
৬৭৩৪
400 grams of sugar solution has 30% sugar in it. How much sugar should be added to make 50% in the solution?
উত্তর
160 grams
৬৭৩৫
A train running at a certain speed crosses a 496-meter-long platform in 56 seconds. If the length of the train is 560 meters, how long will it take to cross a bridge that is 100 meters in length?
উত্তর
35 seconds
৬৭৩৬
A mixture of 60 kg contains sand and stone in the ratio 7 : 5. Find the quantity of sand to be added to the mixture so that the ratio of sand to stone becomes 2 : 1.
উত্তর
15 liters
৬৭৩৭
Two trains are running in the same direction at 80 km/h and 60 km/h. The faster train crosses a man in the slower train in 36 seconds. What is the length of the faster train?
উত্তর
200 meters
৬৭৩৮
A biker was riding at 60 km/h, but if he had gone at 80 km/h, he could’ve gone 100 km more in the same time. How far did he actually travel?
উত্তর
300 km
৬৭৩৯
A person has two acid solutions — one containing 40% acid and the other 60% acid. In what quantities should he mix each to obtain 10 liters of a 50% acid solution?
উত্তর
5 liters
৬৭৪০
A boat travels at 12 km/h in still water, and the stream's speed is 3 km/h. If a boatman rows 90 km to a destination and comes back, how much time does he take in total?
উত্তর
16 hours