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
(More Questions for each concept available in Login)
Question : 1

A train travels at a certain average speed for a distance of 60 km and then travels a distance of 48 km at an average speed of 4 km hr more than its original speed. If it takes 5 hours to complete the total journey, what is its original average speed ?

Right Option : C
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Question : 2

Had Anita scored 10 more marks in a mathematics test of 30 marks, 9 times these markes would have been the square of her actual marks. How many marks did she get in the test?

Right Option : B
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Question : 3

A group of stuydents decided to buy a tape recorder from 170 to 195 ruppes.But at the last moment two students backed out of the decision so that the remaining students had to pay 1 rupee more than they had planned,  The price of the tape recorder if each student paid equal shares is:

Right Option : B
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