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

is it possible to draw a triangle with angles 150°, 10° and 10°
A piece of paper will provide protection from a. alpha radiation. b. beta radiation. c. gamma radiation. d. gamma rays.
Two different ways to find the difference for 12-3
Brianna is getting materials for a chemistry experiment her teacher gives her a container that has 0.15 L of liquid in it Breonna needs to use 0.4 of this liqui
Is 36/54 the same as 48/72?
How do parallel lines improve the following situations? a.- planting crops in parallel rows. b. parallel mirrors in hair salons c. parallel & perpendicular
Relate the statement you can't get something for nothing to the law of conservation of mass
Which of the following is perpendicular to the line y= -1/2x+8
how many time can 21 go into 6
Where and when did the French language start and end?