1. Word Problems

a)Subtract the sum of the predecessor of the largest 4 -digit number and the successor of the least two digit number from th sum of the predecessor of the largest 7-digit number and the successor of the lease 3-digit number .

b) three bells toll ar intervals of 12,16,24 minutes . If they begin to toll toghether at 8 am, at what time will thhey toll toghether

Answer : 

1 ) We know largest 7 digit number  =  9999999 
And predecessor of that number  =  9999998
We know least 3 digit number =  100
And successor of that number  = 101
And sum of these numbers = 9999998 + 101  = 10000099

And
We know largest 4 digit number  = 9999 
And predecessor of that number  =   9998 
we know least 2 digit number  = 10 
And successor of that number  = 11
Sum of these two numbers  =  9998 + 11  = 10009 

Now we subtract them  = 10000099 - 10009   = ​9990090                           ( Ans )

2 )  given : ​Three bells toll at intervals of 12,16,24 minutes 
So to find out at what time they will toll together as they toll at 8 am , 

we find L.C.M. of these given time interval As  :

So LCM of these numbers  =  2 × 2 ××× 3    =  48 

SO,

Next time three bells toll together at 8 : 48 am                                    ( Ans )
 

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(a). 9989889

(b). at 8:48

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