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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Explanation
Question : 2

A businessman knows that the price of a commodity will increase by Rs. 5 per packet. He buys some packets of the commodity for Rs. 4500. If he buys them on new price, then he will get 10 packets less. Find the actual number of packets bought by him.

Right Option : C
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Explanation
Question : 3

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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Explanation
 
 


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