Okay, so if you play for thirty minutes each day and there are seven days in a week, so do 30 times 7 and you have your answer.
He wrote the number 1892, because:
The number needs to be less than 2000, with four digits. Because the first is half the last, it means that the number must be 1??2.
These two numbers add up to 3, and all together, they need to add to 20. 20-3=17. The remaining numbers need to add to 17.
The only two single digit numbers that can add to 17, are 8 and 9. Therefore, the number must either be 1892 or 1982.
The second digit needs to be even, meaning that the number has to be 1892.
I hope this helps.
Your answer would be 14.978
Answer:
There are 10⁻⁷ hydrogen ions in one-liter water
Step-by-step explanation:
Hi there!
a. If the pH = 7.0, then:
-log(H) = 7.0
multiply both sides of the equation by -1
log(H) = -7.0
Apply 10ˣ to both sides
10^(log (H)) = 10⁻⁷
(H) = 10⁻⁷
There are 10⁻⁷ hydrogen ions in one-liter water.
Why 10^(log (H)) = (H)?
Let´s consider this function:
y = 10^(log x)
(Apply log to both sides)
log y = log 10^(log x)
(Apply logarithmic property: log xᵃ = a · log x)
log y = log x · log 10
(log 10 = 1)
log y = log x
y = x
(since y = 10^(log x) and y = x):
10^(log x) = x
That´s why 10^(log (H)) = (H)
The reason it would in crese is because they combin their money