Since there is no repetition allowed, there are 10 possibilities for the 1st digit, 9 for the 2nd, 8 for the 3rd, and 7 for the 4th. This gives a total of (10)(9)(8)(7) = 5040 four-digit codes.
For all odd digits to be used, there are 5 possibilities for the 1st digit (1,3,5,7,9), 4 for the 2nd, 3 for the 3rd, 2 for the 4th. This gives a total of (5)(4)(3)(2) = 120 codes that only use odd digits.
Therefore there are 5040 - 120 = 4920 codes that do not consist of all odd digits. The probability is 4920/5040 = 41/42.
if a b 9 are in GP
b÷a = 9 ÷ b
b^2 = 9a
if a - 1 b 9 are in AP
2b = a+8
b = a+8÷2
substitute
b is equal to a + 8 by 2 in b square equal to 9 a
(a+8÷2)^2 = 9a
a^2+16a+64 = 36a
a^2 -20a +64 =0
(a-16) (a-4) =0
a= 16 or a=4
when a=16 b= 12
when a=4 b= 6
Value of a and b are given above
Answer:
Step-by-step explanation:
To solve this problem is multiply 2 by 2 and then 2 which gives you 8.
Then you will add 2+2+2 and get six. For when multiply exponents you are adding.
Answer:
it 1/3
Step-by-step explanation:
2/4 is just 1/2, 3/6 is also 1/2, 7/9 is over 1/2 and 1/3 is the only one less then 1/2 so it's the lowest fraction. This is not the proper way to solve it but it works and it's faster
