bbyggigi6634 bbyggigi6634
  • 04-09-2017
  • Mathematics
contestada

How many 7 digit phone numbers are there assuming the first digit can't be a 0 or a 1?

Respuesta :

Аноним Аноним
  • 04-09-2017
The first digit can be any one of the numbers 2-9 That a total of 8 numbers.

The next 6 digits can be any permutation of 6  from the numbers  0 to 9.
(10 numbers)

nPr  =  n! / r!

so here we have  10P6  = 10! / 6!  =  10*9*8*7  =  5040

So final answer  is 8 * 5040 = 40,320
Answer Link

Otras preguntas

8sin2θ+2sinθ−1=0 for all values of θ between 0∘ and 360∘.​
"Managing human resource job in organization is becoming stressful day by day due to emerging human resource issues." Discuss.
PLEASE HELP. (Find the area of park)
Provide an appropriate response. Find the z-score that corresponds to the given area under the standard normal curve. please explain how you got your answer
What changes have occurred in Paul in the book a Lesson Before Dying
A board with 2.3m in length must be cut so that one piece is 30cm more than the other piece . Find the length of each piece
check your answer for x= -2/3 5(3x+4)-8(6x+7)=9x-8​
How much gravity does it require to stop time
If Chandani had 600 left after spending 75% of her money, how much did she have in the beginning? 5% this year
check the given picture below.