Math Tricks For Competitive Exams

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Q. Radius of a circle is increased by 10 %, find the percentage increase in area. Ans. You can get the answer by using the formula below: Percentage increase in the area =   Percentage increase in the...

Q. A man sales an article at 10% gain. Had he sold at for Rs. 60 more he could have gained 20%. What is the C.P of the article. Ans. The Formula is as under. C.P = more gain X 100   = 60 X 100  = 600...

Q. What is the time required by a 110 m long train to cross a tunnel 220 m       long at rate of 22 m/s Ans. The formula for this is as below. Time = Distance  = 220+110 = 15 s              Speed            22 Q. A train running at the...

Q. The difference between the compound interest and simple interest on a certain sum at 10% p.a for 2 years is Rs. 631.Find the sum. Ans. The formula is as under. Sum = Diff X 100 X 100            ...

Q.The tax on a commodity is diminished by 20% and its consumption      increases by 15%. Find the effect on revenue. Ans. X = -20 since the tax is diminished         Y = 15 since consumption is...

Q. Circumference of a circle is 44 cm.Find it's area. Ans. The formula for finding the area of the circle when the circumference is given is as below. A =      A =      A =   If...