probability of getting black card an ace =2/52=1/26
Answer:
13.2 years
Step-by-step explanation:
The decay rate is 15%, so the decay factor is 1 - 15% = 0.85. Then the exponential equation for the value is ...
v(t) = 85000·0.85^t
We can set v(t) = 10,000 and solve for t:
10000 = 85000·0.85^t
10000/85000 = 0.85^t . . . . divide by 85000
log(2/17) = t·log(0.85) . . . . . .reduce fraction, take logs
t = log(2/17)/log(0.85) ≈ 13.2
It will take about 13.2 years for the value to fall below $10,000.
_____
Such a question is nicely answered by a graphing calculator.

This is what is in the middle of the second paragraph. That statement is correct.
I don't know that it is any simpler or not, but what they have done in the answer is rationalize the denominator. That means that the denominator is no longer under the square root sign.
To get that result, you multiply numerator and denominator by √F
When you do that, your get

This results in the middle answer.
