Chain Rule

1.If 15 toys cost Rs.234,what do 35 toys cost?

Sol:

No. of toys                    total  cost

  15                                  Rs.234

  35                                    A

A=[15 toys then Rs234, 35(more)  toys  A( more)  cost  so  min(15) will be denominater]

   =(234x35)/15

Hence cost of 35toys is Rs.546/-

2.If 36 men can do a piece of work in 25 hrs,in how many hours will 15 men do it?

Sol:

No. of men               working hrs

36                                    25hrs

15                                   A

A=[36 men then 25hrs ,15(less)men A(more) hrs so 15(min) will be denominater]

  =(36x25)/15=60hrs

Hence 15 men can do  a work in 60hrs/-.

3. If the wages of 6men for 15days be Rs.2100,then find the wages of 9 men for 12 days.

Sol:

Men       days                 wages

6             15                       2100

9             12                         A

A=[6men  then wages=Rs2100,9 men then more(A) wages so min (6)be denominater]&&[15days

      then wages=Rs2100,12days then less(A) wages so max(15) will be denominater ]

=[9x12x2100]/(6x15)

4.If 9engines consume 24metric tonnes of coal,when each is working 8hrs a day,how much coal will be required for 8 engines,each running 13 hrs a day,it being given that 3engines of former type consume as much as 4 engines of latter type?

Sol:

No. of engines                 hrs in a day             consumption ratio              tonnes

9                                          8                                      1/3                                        24

8                                         13                                     1/4                                        A

                                  

A=[9engn=24tonnes then 8engn=less tonnes,so more (9) will be denominater]&&

    [8hrs=24tonnes then 13hrs=more(A)tones so min(8) will be denominater]&&

    [1/3=24 then ¼=less(A)tones so more(1/3) will be denominater]

=[{8x13x(1/4)}x24]/{9x8x(1/3)}=26tonnes