Answer:
2.9 years
Step-by-step explanation:
Given that :
Half-life t1/2 = 9 years
Initial mass = I = 70 grams
A = final mass = 56 grams
t = time taken to reach final amount
Using the exponential half life relation :
A = I(0.5)^t/t1/2
56 = 70(0.5)^t/9
56/70 = 0.5^t/9
0.8 = 0.5^t/9
Log 0.8 = log 0.5^t/9
−0.096910 = −0.301029 * t/9
t/9 = 0.096910 / 0.301029
t/9 = 0.3219291
t = 0.3219291 * 9
t = 2.8973619
t = 2.9 years
Answer: 10
use (PEMDAS)
P parentheses ()
E exponents
M multiplication • , () , x
D division
A addition +
S subtraction -
Explanation:
There are no parentheses.
There are exponents.
The multiplication is the exponents.
There is division.
There is addition and subtraction.
-how to solve-
First, do 2 to the second power and get 4.
Next, do 12-2+4 divided by 8.
Next do multiplication: there’s no more.
Next do division: you can’t do 4 divided by 8 so instead, do 12-2 = 10 plus 8.
Hope this helps!
Answer:
average speed for the entire trip is 15 mph
Step-by-step explanation:
Let x be the uphill speed and y be the downhill speed.
We have been given that
Speed of Omar in uphill to reach gift store = x =10 mph
Speed of Omar in downhill to reach his home = y = 30 mph
We know the formula for average speed for the entire trip
Therefore, average speed is 15 mph
