Jody checked the temperature 12 times on Monday, and the last digit of the temperature was odd six times more than it was even. On Tuesday, she checked it 18 times and the last digit was odd eight times more than it was even. Determine which series is closer to the 50/50 ratio of odd/even expected of such a series of temperature checks.

A. The Monday series is closer because 1/6 is closer to 1/2 than is 1/8.
B. The Monday series is closer because 6/12 is closer to 0.5 than is 8/18.
C. The Tuesday series is closer because the 13/18 is closer to 0.5 than is 9/12.
D. The series closest to the theoretical 50/50 cannot be determined without knowing the number of odds and evens in each series.

To determine which series is closer to the 50/50 ratio of odd/even expected, let's analyze the given information.

On Monday, Jody checked the temperature 12 times. The last digit of the temperature was odd six times more than it was even. This means that the number of odd last digits is 6 more than the number of even last digits.

To find the number of odd and even last digits on Monday, we can set up the following equation:
even + 6 = odd

Since Jody checked the temperature 12 times, the total number of last digits is 12. Therefore, we get:
even + even + 6 = 12

Simplifying the equation, we have:
2 even = 6
even = 3

So, the number of even last digits on Monday is 3, and the number of odd last digits is 3 + 6 = 9.

On Tuesday, Jody checked the temperature 18 times. The last digit was odd eight times more than it was even. This means that the number of odd last digits is 8 more than the number of even last digits.

Setting up the equation for Tuesday, we have:
even + 8 = odd

Since Jody checked the temperature 18 times, the total number of last digits is 18. Therefore, we get:
even + even + 8 = 18

Simplifying the equation, we have:
2 even = 10
even = 5

So, the number of even last digits on Tuesday is 5, and the number of odd last digits is 5 + 8 = 13.

Now, let's compare the ratios of odd to even last digits for each series.

For Monday:
The ratio of odd to even last digits is 9/3 = 3/1 = 3. This means that for every 3 odd last digits, there is 1 even last digit.

For Tuesday:
The ratio of odd to even last digits is 13/5. This ratio cannot be simplified further.

To compare these ratios to the theoretical 50/50 ratio, we convert them to decimals and see which one is closer to 0.5.

For Monday:
The ratio 3/1 is equal to 3. Since 3 is greater than 0.5, the Monday series is not closer to the 50/50 ratio.

For Tuesday:
The ratio 13/5 is equal to 2.6. Since 2.6 is less than 0.5, the Tuesday series is closer to the 50/50 ratio.

Therefore, the correct answer is: C. The Tuesday series is closer because the 13/18 is closer to 0.5 than is 9/12.

To determine which series is closer to the 50/50 ratio of odd/even, we need to compare the fractions of odd numbers to the total number of temperature checks for each day.

First, let's analyze the Monday series:
- Jody checked the temperature 12 times on Monday.
- The last digit of the temperature was odd six times more than even.
- This means there were 6 even temperatures and 6 + 6 = 12 odd temperatures.

The fraction of odd temperatures is 12/12 = 1, and the fraction of even temperatures is 6/12 = 1/2.

Next, let's analyze the Tuesday series:
- Jody checked the temperature 18 times on Tuesday.
- The last digit of the temperature was odd eight times more than even.
- This means there were 5 even temperatures and 5 + 8 = 13 odd temperatures.

The fraction of odd temperatures is 13/18, and the fraction of even temperatures is 5/18.

Now, let's compare the fractions to determine which series is closer to the 50/50 ratio.

A. The fraction for the Monday series is 1/2 for even and 1 for odd. This is not closer to 0.5 (50/50).
B. The fraction for the Monday series is 1/2 for even and 1 for odd. This is not closer to 0.5 (50/50).
C. The fraction for the Tuesday series is 13/18 for odd and 5/18 for even. This is closer to 0.5 (50/50).
D. This cannot be determined without knowing the number of odds and evens in each series.

Therefore, the correct answer is C. The Tuesday series is closer because the fraction 13/18 is closer to 0.5 than the fraction 5/18.