Category > General Science (Chemistry) Practice Sets For WBCS Prelim

Q. Whose presence in drinking water is welcome?

Answer : K


Asked Question

Q 1. 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 2. Rs. 7500 has been borrowed at 4% annual compound rate of interest. How much money will have to be returned after two years?

Q 3. 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?

Q 4. In a hundred metres race, A defeats B by 10 metres and C by 13 metres, then in the 10 metres race by what distance will B defeat C?

Q 5. When two pipes work together, then a tank can be filled in 12 hours. One pipe fills the tank comparatively 10 hours faster than the other pipe. How much time will the pipe which is faster take to fill the tank?

Q 6. A boy goes from home to school at the rate of 3 km./hr. and come back from school to home at the speed of 2 km./hr. If he takes five hours in coming and going, then what is the distance between home and school?

Q 7. A man rows a boat at the speed of 6 km./hr. in still water. When the river flows with the speed 1.2 km./hr, then it takes 1 hour for the man to row from one place to another. How far is that place?

Q 8. Find out the area of a triangle whose sides are 50m., 78m., and 112m.?

Q 9. If the length of a rectangle is reduced by 20%, then by what percent should its width be increased so that the area does not increase?

Q 10. A train 110 metres long is travelling at the speed of 60 km. per hr. How long will it take to cross a man walking in the direction opposite to the train, at the speed of 6 km./hr.?

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