Answer:
The sample would double in 9 hours
Step-by-step explanation
The number of hours it will take for the sample to double can be found using the 72 rule.
The 72 rule is such that a growth rate would double itself by it is used in dividing the number 72 as shown below:
number of hours =72/8=9 hours
The number of hours it would take the sample to double is 9 hours as computed above.
(10 2/3)/(11/20)
(32/3)/(11/20)
(32/3)*(20/11)
640/33
19 13/33 since DVDs are integer units Mr. Washington can only have 19 DVD's side-by-side.
Let the speed of the current be y and the speed of Micah's sailing speed be x. Then 4.48/(x + y) = 0.32
4.48/(x - y) = 0.56
0.32x + 0.32y = 4.48 . . . (1)
0.56x - 0.56y = 4.48 . . . (2)
(1) x 7 => 2.24x + 2.24y = 31.36 . . . (3)
(2) x 4 => 2.24x - 2.24y = 17.92 . . . (4)
(3) - (4) => 4.48y = 13.44
y = 3
From (1), 0.32x + 0.32(3) = 4.48
0.32x = 4.48 - 0.96 = 3.52
x = 3.52/0.32 = 11
Therefore, the speed of the current is 3 miles per hour.
(50/4) + (6/4) is the answer that you are looking for. All you do is break up the number that you are going to divide into easy-to-divide numbers.
