Answer:
4 hours
Step-by-step explanation:
The amount remaining at the end of each hour is 0.85 of the amount at the start of the hour. You want to find the exponent such that ...
... 0.85^x = 0.5 . . . . . x = the number of hours until half is left
... x·log(0.85) = log(0.5) . . . . . take the log to turn it to a linear equation
... x = log(0.5)/log(0.85) ≈ 4.265024
Rounded to the nearest hour, x = 4.
Answer:89%
Step-by-step explanation: its the probability that they will get anything other than an arm tattoo. So you subtract 43 from 389 and it gives you 346,
346/389 x 100% = 88.9%
On the right side, there are
• 2•2 = 4 atoms of Nb
• 2•5 = 10 atoms of O
so among the reactants on the left, the reaction is balanced as
4 Nb + 5 O₂ → 2 Nb₂O₅
√11 √5 = √(11 * 5) = √55 = approx 7.42 (rounded)
