28 men are needed to paint the room in 3 hours
<h3><u>Solution:</u></h3>
Given that it takes 12 hours for 7 men to paint a room
We are asked to find number of men required to paint the room in 3 hours
Recognize, "paint the room" is 1 task. One job.
7 men -------- 12 hours ------ 1 job
(7/7) = 1 men ------- 12 x 7 (84) ------- same 1 job
The one men is rate is 84 hours to do the job
We can express this as 1/84 jobs per hour, the one-person rate
Now lets find how many men needed to paint the room in 3 hours
Let the required number of men for 3 hours be "a"
The rates of each person is simply additive.
corresponds to rate x hours = jobs and "a" is a variable for how many men
Thus 28 men are needed to paint the room in 3 hours
Answer:
gift 1:
424 cm^2
570 cm^3
gift 2:
1420.5 cm^2
3622.5 cm^3
Step-by-step explanation:
We have to calculate the surface area of these gifts in order to know the amount of wrapping paper.
The formula for the surface area is:
A = 2*ab + 2*ac + 2*bc
Gift 1:
A = 2*6*10 + 2*6*9.5 + 2*10*9.5
A = 424 cm^2
That means that gift 1 needs 424 cm^2 of wrapping paper
Gift 2:
A = 2*14*17.25 + 2*14*15 + 2*17.25*15
A = 1420.5 cm^2
That means that gift 2 needs 1420.5 cm^2 of wrapping paper
Now, to calculate the cubic centimeters of packaging peanuts, we calculate the volume, the volume has as formula:
V = a*b*c
Gift 1:
V = 6*10*9.5
V = 570 cm^3
This means that gift 1 needs 570 cm^3 of packaging peanuts
Gift 2:
V = 14*17.25*15
V = 3622.5 cm^3
That means that gift 2 needs 3622.5 cm^3 of packaging peanuts
Because every number in this is important to the number it is 3. If the zero wasn't significant, then it would just be 15. A non-significant 0 would be like, 1.000