Answer:
(a) 0.0001 or 0.01%
(b) 0.01 or 1%
Step-by-step explanation:
Since there are 10 possible numeric digits (from 0 to 9), and there is only one correct digit, there is a 1 in 10 change of getting each digit right.
The probability that if you forget your PIN, then you can guess the correct sequence
(a) at random:

(b) when you recall the first two digits.

It would be $2.25
if each student pays one more penny than the last one the penny count would be up to 150 pennies times the number of student which is 150 so multiply and add your decimal
Since they tell us that this is linear, having a constant rate of change, we can express this as a line:
y=mx+b, where m=slope (change in y divided by change in x) and b=y-intercept (value of y when x=0)
First find the slope, or m, which mathematically is:
m=(y2-y1)/(x2-x1), in this case:
m=(880-440)/(2000-1000)
m=440/1000
m=0.44, so far our line is:
y=0.44x+b, now we can use either data point to solve for b, I'll use (1000,440)
440=0.44(1000)+b
440=440+b
0=b, so our line is just:
y=0.44x
Answer:
C.
Step-by-step explanation:
If 4ab+k=13 then k=13-4ab