Answer: 12 hours
Step-by-step explanation:
Given : Working together, it takes Sam, Jenna, and Francisco two hours to paint one room.
When Sam works alone, he can paint one room in 6 hours. When Jenna works alone, she can paint one room in 4 hours.
Let 't' be the time taken by Francisco to paint one room on his own.
Then , we have
Rate of work of Sam +Rate of work of Jenna + Rate of work of Francisco =Rate of work they all do together

i.e. 
i.e. 
i.e. 
i.e. 
i.e. 
i.e. 
i.e. t= 12
Hence, Francisco would take 12 hours to paint one room on his own.
Yes, the rules of scientific notation are:
1. All non-zero digits are significant
2. Zeros in between non-zeros are significant.
3. Zeros to the left of the first non-zero number are NOT significant.
4. Zeros to the right of non-zero numbers are significant IF a decimal point is present.
P.S: if you need help with sig fig rounding, let me know.
We know there are 4 suites the deck can be divided into, and two of the 4 are black. So you divide 2/4, and get 1/2. So the probability that a black card will be chosen is 1/2.
Answer:
11 weeks
Step-by-step explanation:
5÷1/2=10
10+1=11
Sorry if I'm wrong