Answer:
The information given is not enough to determine their ages explicitly, so, here their ages are given in terms of Anna's age, which is the best that could be determined.
Anna's age = x years
Robert's age = (x - 11) years
Sara's age = (x - 9) years
David's age = (x - 1) years
Step-by-step explanation:
Let Anna be x years old.
Anna's age = x
Because Anna is 11 years older than Robert, we can say Robert's age is Anna's age minus 11.
Robert = x - 11
But Robert is 2 years younger than Sara, we can say Sara's age is Robert's age plus 2
Sara = (x - 11) + 2
= x - 9
David is 8 years older than Sara, we can say David's age is Sara's age plus 8.
David = (x - 9) + 8
= x - 1
We add up all those numbers (excluding 30) and divide by the number of numbers (9). This results in 78.8 (round up to 79).
79-74 = 5. So the mean has increased by 5 points. (C)
Answer:
Mr. Selan would pay $2.15 for the sandwiches with tax.
Step-by-step explanation:
Given that:
Cost of each sandwich = 99 cents
Cost of two sandwiches = 99*2 = 198 cents
Sales tax = 8.5%
Sales tax = 
Sales tax = 17 cents
Total cost = 198 + 17 = 215 cents
Total cost = $2.15
Hence,
Mr. Selan would pay $2.15 for the sandwiches with tax.
Answer:
Step-by-step explanation:
The exponential decrease formula that we must use is:
Where A is the amount of thorium as a function of time
is the initial amount and k is the decrease rate
We know that initially there are 50 gr and that you decay 50% every 1.9 years.
So
We solve the equation for k
After 22.8 years the amount of thorium that exists is:
Answer:
1,2,3,4,6,8,12,16,24,32,48,64,96,128,192,256,384,768
Step-by-step explanation
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