Question 355704


Here we have to create 7 digit phone number.

when first three digit is 345, we can choose any digit 0-9 for each place.

for example- 3450000, 3450005, 3452010 and so on.



For each place, no. can be choose by 10C1 = 10 


so, total no. of ways = 10 * 10 * 10 * 10 = 10000


similarly,  for 286  and 329 there are 10000 possible no. can be formed.


total no. of 7 digit number if the first three digitd sre either 345, 286 or

329.    =  10000 * 3 = 30000




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