Statement sum Involing Quadratic Equations


 
 
Concept Explanation
 

Statement sum Involing Quadratic Equations

Statement sum Involving  Quadratic Equations:

Step 1: Translate the word problem into methamatical statement.

Step 2:  Then form a Quadratic Equation.

Step 3: Solve the Quadratic Equation.

Step 4: Reject the root that satisfy the conditions of the problem.

Example: The Sum of two numbers is 18 and their product is 45. Find the numbers.

Solution: Let one number = y

 Other number = 18- y

According to the question:

Product = 45

y X (18-y) = 45

large 18y-y^2=45

large -y^2+18y-45=0

large y^2-18y +45=0

large y^2-15y -3y+45=0

large y(y-15) -3(y-15)=0

large (y-15) (y-3)=0

large Either ;(y-15) =0 ;or; (y-3)=0

y= 15 , 3

So One number is 15 and the other number is 3

Sample Questions
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Question : 1

One side of a rectangle is 4cm shorter than three times the other side. Find the sides if the area of the rectangle is large 319cm^2 .

Right Option : D
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Question : 2

At 't' minutes past 4 p.m, the time needed by the minute-hand of a clock to show 5 p.m. was found to be 3 minutes less than t^2/4 minutes. Find the value of t.

Right Option : C
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Explanation
Question : 3

A number is multiplied by    large frac{1}{3}    times itself and 18 is added to the result. If the final result is 2901, the number is _________________

Right Option : B
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Explanation
 
 


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