SHORTCUTS,TRICKS,TIPS FOR QUANTITATIVE APTITUDE- RATIO AND PROPORTIONS

SHORTCUTS,TRICKS,TIPS FOR QUANTITATIVE APTITUDE RATIO AND PROPORTIONS:

RATIO AND PROPORTION:


In the previous post regarding SHORTCUTS,TRICKS,TIPS FOR RATIO AND PROPORTIONS I have given introductory explanation.Now I am going to explain detailed concept
about  RATIO AND PROPORTIONS.

Here i am going to explain the problems which are often in the exams and my method is exam oriented method which is very helpful to you to solve the problems.

I am going to build the concept while solving the problems only .Here i am giving the some problems
regarding  RATIO AND PROPORTIONS.

Find the fourth proportion of 60, 72 and 25?

1) 20                    2) 42                    3) 28                    4) 30                    5) None of these

Find the fourth proportion of 48, 72 and 24?

1)63            2)36                    3)24            4) 42                    5) None of these

The third proportion of 12 and 6 is?

1)5              2)6              3)3              4)4              5) None of these

The third proportion of 36 and 24 is?

1) 16           2)18            3)24            4) 12           5) None of these

The mean proportion of 36 and 81 is?

1) 50           2)54            3)45            4) 40           5) None of these

The mean proportion of 48 and 147 is?

1) 84                    2) 48           3)60            4) 30                    5) None of these



firstly let us examine the above problems , what the questions are asking

these questions are asking about proportion ok

concept:

Fourth proportional to a,b,c is  b*c/a

Third    proportional to a,b is    b*b/a

Mean proportional to a,b is       square root of a*b

Now we are going to solve the problems by using above concept of  SHORTCUTS,TRICKS,TIPS FOR RATIO AND PROPORTIONS

1.Find the fourth proportion of 60, 72 and 25?

1) 20                    2) 42                    3) 28                    4) 30                    5) None of these

 solution:
  a=60 b=72 c=25

   there fore b*c/a ----72*25/60=30 so our option is 4


2.Find the fourth proportion of 48, 72 and 24?

1)63            2)36                    3)24            4) 42                    5) None of these

solution:try yourself

3.The third proportion of 12 and 6 is?

1)5              2)6              3)3              4)4              5) None of these

solution:a=12 b=6

third proportion formula=b*b/a=6*6/12=3 so our answer is option 3

4.The third proportion of 36 and 24 is?

1) 16           2)18            3)24            4) 12           5) None of these

solution:try yourself

5.The mean proportion of 36 and 81 is?

1) 50           2)54            3)45            4) 40           5) None of these

solution:mean proportional to a, b is square root of a*b=square root of (36*81)

           square root of 36=6

              square root of 81=9
therefore 6*9=54 so option 2 is our answer
      
for more problems on Ratio and proportion (see the link)