CLASS-8
WORD PROBLEM & SOLUTION OF FRACTION

WORD PROBLEM & SOLUTION 

Example.1) Jack has a packet of 20 balls, he gave ¼ to Frank and 1/5 of the remaining to Harry, of the rest he gave 1/3 of the remaining to Richard. Find the number of balls finally left with Jack. what fraction of the packet was left with him ?               

                                                                                                                                    

Answer.) As per the given condition, Frank got number of balls =     

           1

 20 X ------- =  5 balls

           4

So, remaining balls =  20 – 5 = 15 balls                      

                                                                         1

Harry received number of balls  = 15 X --------  = 3 balls

                                                5

Remaining balls = 15 – 3 = 12 balls                                                                                                                                                                                   1      

Richard received number of balls  =  12  X -------- =  4 balls

                                                    3

Remaining balls =  12 - 4  =  8 balls                                                                                                      

As per the given condition, the required fraction is  

            8              2

=  --------  =  --------               (Ans.)

       20              5



 

Example-2)  8/15 of a number exceeds 4/25 of the number by 140, find the number.

Answer)   let the required number is  z

As per the given condition  if one number is 8z / 15, then another would be 4z / 25, so according to that condition.    

 

       8z               4z

  ----------  -  ---------  = 140

       15               25

 

          ( 8z X 5 )  -  ( 4z X 3 )

=> -----------------------------  =  140

                      75


             40z – 12z

=>    ----------------- =  140

                 75

 

=>     28 z  =    140 X  75


                  140 X 75

=>   z   =  --------------  =  5 X 75 =  375

                     28

So, the required number is  375     (Ans.)




 

Example.-3) Richard’s monthly salary is $ 3500, he pays 1/10 of his salary as tax and spends 7/45 of the remaining on the education of his children. 1/5 of the rest is paid as the rent of the house and $1000 is spent on food & conveyance. Find Richard’s monthly savings.

                                               1

Answer)   The amount paid as Tax  =  -------- X  3500  =  350

                                              10 


The remaining amount = $ 3500 - $ 350 =  $ 3150      

                                                         7

Amount spent of Children’s education =  3150 X -------- = $ 490

                                                        45

Remaining amount is = $ 3150 - $ 490 =  $ 2660


Now he spend as house rent 1/5 of the rest amount, so the rent amount is    

                            1

=  $ 2660 X ------- =  $ 532

                  5

Remaining amount = $ 2660 - $ 532 =  $ 2128

He spent $1000 on food & conveyance = $ 2128 - $1000 = $ 1128

Hence, Richard’s monthly savings is $ 1128.   (Ans.)




 

Example.4)  If 3/20 of a number is less than 7/10 of the number by 110, then find the number.

Answer)  Let the required number is x.

As per the given condition if one number is 3x / 20, then another would be 7x / 10, so according to that condition     

       7x             3x

    -------  -  --------  =  110

       10             20

 

          ( 7x X 2 ) - ( 3x X 1 )

=>   -------------------------  =  110

                     20

           14x – 3x

=>    --------------  =  110

               20 


=>     11 x  =  110 X  20


                110 X 20

=>   x  =  --------------  =   10 X 20  =  200

                    11

So, the required number is  200     (Ans.)