10% chance of burning out
100-10= 90% chance of not burning out
90% = 0.9
3 lightbulbs
0.9^3 = 0.729 = 72.9%
The probability that all 3 lightbulbs stay lit by the end of the month is 72.9%
Answer:

Step-by-step explanation:
By definition, we can write ln instead of log. WHEN??
Whenever the base of the logarithm is the number "e".
Hence, when we have:

We can write it in shortcut as:

Hence, ln x can also be written as 
Fourth answer choice is right.
Answer:
6(4x+3y)
Step-by-step explanation:
24 and 18 have a HCF of 6, so yeah