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

Which of the following is NOT one of the three reactants needed for a green plant to make its own food.
what is the solution
Solve this inequality for x. -46-8x>22
what is the slope of the line that passes through the points (-1,-7) and (-2,-5)
Which is an example of the consequences of unhealthy eating? An adult female prevents bone loss by eating adequate amounts of vitamins and minerals. An active
To save on heating bills, do you think the roof of a building should be lined with1. a thermal conductor2. a thermal insulator3. nothing
what describes absorption
What was the driving force behind the highlighted country's independence in 1964? A) Fighting between the Muslims and the Christians led to the independence mov
Describe your morning routine. Using nouns, specific adjectives, and vivid verbs.*Remember to consider all 5 of your senses.
Do you agree or disagree with the acts of those who illegally stormed and temporarily took over our capital? Why? Thinking about peace, love, and liberty, what