Latest math tip

To solve a sum dealing with number of men and number of days taken to complete a work use the logic:  1 person takes 1 day to complete 1 unit of work.
If 20 men take 20 days to complete a work, How many days it will take 40 men take?
Assume 1 person takes 1 day to complete 1 unit of work. 20 men complete 20 units in 1 day. So in 20 days, 400 units is completed.
Hence 40 men will complete 40 units in 1 day and 40 men will complete 400 units in 10 days.
Answer is 10 days.

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5 most overlooked points while solving GMAT triangle based problems (under Geometry)

1. Similar triangles are triangles whose sides are proportional. If ABC and PQR are two similar triangles then AB/PQ = BC/QR =AC/PR. The angles opposite to the sides(which are in a ratio) are also proportional  
   
2.   Area of a triangle(sides are a,b,c) is based on the hero’s formula 

           

          s= (a+b+c)/2 , R = circum radius and r= inradius

  3.   The sum of two sides of a triangle is greater than or equal to the third side and the difference of any    

      two sides is lesser than or equal to the third side. This property is used extensively in GMAT higher

           difficult problems

    4.    For the equilateral and the isosceles triangle the altitude bisects the base and hence the triangle into
           two equal parts

    5.    The largest triangle (with the maximum area) which can be inscribed in a circle is the equilateral
           triangle.