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य र व ल अपने देश के कई भागों में इधर-उधर ताम्बा काफी मात्रा में बिखरा पड़ा है। जमीन के ऊपर बने छेद से तेजाबी घोल डाला जाए तो ताम्बा उसमें घुल जाएगा। विस्फोट करने से जमीन के अन्दर का ताम्र अयस्क भण्डार टूट-फूट जाएगा। इसके लिए न्यूक्लियर विस्फोट बहुत उपयोगी सिद्ध हो सकता है। पारम्परिक तरीकों से इसे निकालने में बहुत खर्च आएगा। इस द्रव ताम्बे को ऊपर खींचा जा सकता है।
A train crosses a man in 12 seconds and a platform 480 meters long in 36 seconds. Calculate the time (in seconds) it takes for the train to overtake a b...
An athlete running at three-quarters of her average speed takes 25 minutes extra than her usual time to finish a marathon. Find her usual time to finish...
A train would take 20 seconds to cross a stationary pole. If the train was 200m shorter, it would have taken 10 seconds less. Find the speed of the train.
A car running with a speed of 65 km/hr takes 12 hours to go from 'A' to 'B'. If on the way back from 'B' to 'A', the car takes 20% less time than it tak...
A and B move towards each other at the same time at the speeds of 15 km/h and 25 km/h, respectively and the distance between them is 60 km. How much is ...
A train is travelling at the rate of 72 km/hr. How many seconds it will take to cover a distance of 2/5 km?
Car' A' travels at the speed of 65 km/hr and reaches its destination in 8 hours. Car 'B' travels at the speed of 70 km/hr and reaches its destination in...
A driver of truck sees an ambulance 160 meters ahead of him. After 20 seconds the ambulance is 140 meters behind. If the speed of the truck is 80 kmp/h,...
If a man covers a distance in 1 hour, walking at a speed of 5 km/hr, how long will it take him to cover 15 km?
A car completes a journey in 6 hrs with a speed of 50 km/hr. At what speed must it travel to complete the journey in 5 hrs?