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

If you had a broom of your own, what would you like to do with it and where would you like to go? i am a potter head hehe
Help me at least for the first and third question pls thales exercise.
HELP FAST 15 POINTS a) between 0 and 1 b) between 1 and 2 c) between 2 and 3 d) between 3 and 4
We often think of technological change as good for society. Give an example of an instance when technology has created or increased a public health issue and ev
PLEASEEE HELPPPPPP GIViNG POINTS
Building empires would be included in which theme of historical study?
2sinx / cos3x = tan3x - tanx -verify the identity-
please answer with clear instructions so that i can apply this to other equations
the area of triangle is 38.5 cm. help me solve this question. thanks ​
8)What number is 60% of 140?