Answer: it will take 9 hours.
Step-by-step explanation:
The rain is falling at the rate of 1.5 inches per hour. This means that the height of water in the barrel is increasing in arithmetic progression.
The formula for determining the nth term of an arithmetic sequence is expressed as
Tn = a + d(n - 1)
Where
a represents the first term of the sequence.
d represents the common difference.
n represents the number of terms in the sequence.
From the information given,
a = 18 inches
d = 1.5 inches
The expression becomes
Tn = 18 + 1.5(n - 1)
For the number of hours it would take to collect 30 inches of rain in the barrel, Tn = 30
Therefore,
30 = 18 + 1.5(n - 1)
1.5(n - 1) = 30 - 18
1.5(n - 1) = 12
n - 1 = 12/1.5 = 8
n = 8 + 1
n = 9
Answer:
A and C the other two are just stand alone numbers. so the answers are A and C
Answer:
455 or 680, depending
Step-by-step explanation:
If we assume the three choices are different, then there are ...
15C3 = 15·14·13/(3·2·1) = 35·13 = 455
ways to make the pizza.
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If two or three of the topping choices can be the same, then there are an additional ...
2(15C2) +15C1 = 2·105 +15 = 225
ways to make the pizza, for a total of ...
455 + 225 = 680
different types of pizza.
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There is a factor of 2 attached to the number of choices of 2 toppings, because you can have double anchovies and tomato, or double tomato and anchovies, for example, when your choice of two toppings is anchovies and tomato.
_____
nCk = n!/(k!(n-k)!)
Answer:
it's 6
Step-by-step explanation:
B=7 and D=13, so 13-7= 6
