Janet and Marjorie want to buy rolls of material to line rectangular drapes for their rooms. The rectangular piece of material on each roll measures 3 feet by 20 feet. If the total area of the drapes is 150 square feet, how many rolls do they need?

NEED THIS ASAP WITH WORK11

They need 2 and 1/2 rolls.

Step-by-step explanation:

Area = length x width

A = l x w

A = 20 x 3

A = 60 ft²

If 60 ft² = 1 roll

What about 150 ft² = ?

= (150 x 1) ÷ 60

= 150 ÷ 60

= 2.5

= 2 and 1/2 rolls

irst, find the z score of a score of 80. this is given by the formula z = (x-u)/o, where x is the score, u is the mean, and o is the standard deviation. this gives

z = (80-78)/12 = 1/6 = .1667

now, find what percentile a z score of 1/6 correlates to in the normal distribution.

a z score of 1/6 = .1667 is equivalent to the 56.36th percentile of the distribution. so the probability a score is over this is 1-.5636 = .4364

the mean of a sample mean is equal to the original mean. however, the standard deviation of a sample mean is equal to the original standard deviation divided by the square root of n (sample size). so the new standard deviation is 12/sqrt(16) = 3.

the new z score is 80-78/3 = 2/3 = .667. this is equivalent to the 74.86th percentile. so the probability that the mean will be greater than this score is 1-.7486 = .2514.