Category > General Science (Chemistry) MCQs For WBCS Prelims and Main

Q. The highest amount of known element in the earth is

Answer : Oxygen
Explanation: In the earth the most abundant known element is Oxygen(O2). 46.6% of earth mass is Oxygen. In the Universe the most abundant known element is Hydrogen.


Asked Question

Q 1. If 8 men can sow 80 hectares in 24 days, then how many hectares can 36 men sow in 30 days?

Q 2. The LCM of two numbers is 2310 and HCF is 30. If one of the numbers is 210, then what is the other number?

Q 3. In a 30 litre mixture of milk and water, the ratio of milk and water is 7:3. How much water should be added in the mixture so that the ratio of milk and water becomes 3:7?

Q 4. A and B can together do a work in 6 days. A can do it alone in 9 days. In how many days can B do it alone?

Q 5. The average marks obtained by 120 students in an exam is 35. If the average marks obtained by successful students is 39 and the average marks obtained by unsuccessful students is 15 then what is the number of successful students?

Q 6. A train travels from A to B at the speed of 20 km./hr. and from B to A at the speed of 30 km./hr. Then what is the average speed of train in km./hr.?

Q 7. There is a loss of 12 percent on an article being sold for Rs. 352.88, then the cost price of the article is

Q 8. After 5 years, fathers’ age will be three times the age of son. Five years earlier father’s age was 7 times the age of son at that time. What are the present ages of the father and the son?

Q 9. Rs. 7500 has been borrowed at 4% annual compound rate of interest. How much money will have to be returned after two years?

Q 10. A can do a work in 6 days and B can do it in 5 days. The contract for the work is Rs. 220. If A and B work together then how much money should B get?

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