Answer:
2.22 hours
Explanation:
If Sally can paint the office by herself in 5 hours, we can say that in one hour she paints 1/5 of the office.
On the other hand, Lucy paints the office in 4 hours, which means that, in 1 hour she paints 1/4 of the office.
Therefore, to know how much they would paint per hour working together, we are going to sum up the fractions they paint per hour:

Therefore, working together they will paint
of the office in one hour.
Now we can establish a rule of three: if they paint 0.45 of the office in 1 hour, how long (x) will it take them to paint 1.0 of the office?

And therefore 
Therefore, it will take them 2.22 hours to paint the office working together.
Answer:
The concentration of the hormones decreases over time in the tuber (potatoes or tubers are underground swollen stems), allowing the sprouting of tubers. This is a necessity in nature, if potatoes are to eventually reproduce by tubers to produce new plants.”
Explanation:
Answer/Explanation:
Sexual reproduction is a a combination of chromosomes from each mate. Since each mate has different pairs, when combined they produce a completely different product.
This product has half of the characteristics from both sides.
Below is an example of how this works. The bold cells are from one mate and the other is from the other.
X ---> >< <--- X
X ---> >< <--- X
X ---> >< <--- X
X ---> >< <--- X
X ---> >< <--- X
As shown, the cells broke in half and combined with the other half forming a cell of 50/50. With this process it never created an identical offspring but different ones each time since different parts of the cell combines in different ways but still remains half of one and half of the other.
Answer:
The collision occurs at a height of 1/3 of the total height of cliff.
Explanation:
The situation is represented in the attached figure:
For the stone dropped from top of cliff we have
Initial velocity of drop= 0 m/s.
Now the time at which it attains a velocity of 2v is obtained from first equation of kinematics as

Thus the distance it covers in this time can be calculated using third equation of kinematics as

For the stone thrown upwards the velocity at collision is give as 'v' thus the velocity at which it is thrown upwards can be calculated by first equation of kinematics as

The height over which it changes it's velocity from '3v' to 'v' can be again obtained from third equation of kinematics as


Thus the collision occurs at at a fraction of 1/3 of height.
True. Is the correct answer. I am sure of it.