Dr. Iske Larkin stated that she had done some work on nutrition in Manatees. One of the questions that she was interested in was
1 answer:
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Answer:
Proved
Step-by-step explanation:
From the given parameters, we have:
i.e. the length of each security numbers
i.e. 2 security numbers
Required
In 513 security numbers, 2 must have matching zeros
To do this, we make use of Pigeonhole principle.
First, we calculate the number of all security numbers not having matching zeros.
Each of the 9 digits can be selected in 2 ways.
2 ways implies that each digit is either 0 or not
So, total selection is:
Apply Pigeonhole principle
The principle states that: suppose there are n items in m containers, where , then there is at least one container that contains more than 1 item.
This means that if there are 512 security number without matching zeros, then there is 1 (i.e. 512 + 1) with matching zeros.
Answer:
Ivy is 6 years old and Rose is 12 years old.
Step-by-step explanation:
To solve this problem, two variables are necessary since we have two unknown variables: Ivy's age and Rose's age.
Ivy's age will be
and Rose's age will be
"Ivy is half as old as her sister":
this will be our <u>fist equation.</u>
"In six years, Ivy will be two-thirds as old as Rose"
in six years Ivy will have years, and Rose will have
years, so for this sentence we have the equation:
this will be our <u>second equation.</u>
Substituting the value of x from the first equation into the second, and solving for y(Rose):
Rose is 12 years old.
and Ivy (using the fist equation):
Ivy is 6 years old.