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

Any gïrls here free to talk
In this type of governance the power is in the hands of one person​
In 1860 the small towns became a city. true or false
i hate this brainly thing so so so much
i hate this brainly thing so so so much
what is a good question for me to ask that i can put up for 100 points?
Rahi is pouring concrete to create the foundation of a square deck covering 112 square feet. Which is the best estimate of one side of the deck? Round to the ne
Im struggling with these 2 problems
A study investigated about 3000 meals ordered from Chipotle restaurants using the online site Grubhub. Researchers calculated the sodium content (in milligrams
Which of the following statements best describes the formation of volcanoes?