Question

A key code must contain 6 numerals. There are 10 numerals available. Using these numerals, how many different key codes maybe created?
A. 340
B. 210
C. 3,480
D. 151,200

Answer 1

10/(10-6)=10/4.
(10*9*8*7*6*5*4*3*2*1)/(4*3*2*1)
Numbers that are in the numerator and denominator are cancelled out
10*9*8*7*6*5=151200 codes
* means multiply if you didn't know
The correct answer is D

Hope this helped :)