Answer:
6
Step-by-step explanation:
Sum of first 4 numbers= 4*5= 20
This includes 3 + 4th number
Sum of last 4 numbers= 4*8= 32
This includes 4th number + 3
Sum of 7 numbers= 7*(6+4/7)= 46
This includes 3+4th number +3
Number common to both sets= (20+32)- 46 = 6
Answer: never because they are both infinite.
Answer:
Step-by-step explanation:
The logarithm function is monotonic with a positive slope everywhere. So, the logs of numbers are in the same order as the numbers themselves. pH is the negative of the logarithm, so the pH values are in the reverse order of the numbers themselves.
Maura's pool has a lower pH, so will have a higher concentration of hydrogen ions.
The log of a ratio is the difference of the logs. Here, the difference of the logs is 7.8 -7.2 = 0.6, so the ratio of H+ concentrations in the two pools is ...
10^0.6 ≈ 4.0
Maura's pool has 4× the H+ concentration of Bill's pool.
