I saw the image that should have been posted with this word problem.
The rolls of wrapping paper is cylindrical in shape.
Roll A : length = 30 inches ; diameter = 3 inches
Roll B : length = 24 inches ; diameter = unknown
Lateral surface area = 2 π r h
Lateral Surface area of Roll A = Lateral Surface area of Roll B
2 * 3.14 * 1.5in * 30in = 2 * 3.14 * r * 24 in
282.60 in² = 150.72 in * r
282.60 in² / 150.72 in = r
1.875 in = r
diameter is 2 times the radius = 1.875 in * 2 = 3.75 inches
The diameter of Roll B is 3.75 inches.
Answer:
I think it 1188mm but not that sure if someone can double make sure
If Chad can paint the whole room in 5 hours, in 1 hour he gets 1/5 of it painted. If Cassie can paint the whole room in 3 hours, in 1 hour she gets 1/3 of it painted. If we add those together we can find out how much of the room they can paint together in one hour. 1/5 + 1/3 = 1/x, with x being the number of hours it will take them to paint the room together. Common denominator is 15, therefore, 3/15 + 5/15 = 1/x and 8/15 = 1/x. Cross-multiply to get 8x = 15, so it will take them 15/8 hours, or 1.9 hours to paint the whole room together.
