The cost C (in dollars) of making n watches is represented by C = 15n + 85 .
1 answer:
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Answer:
= 1+2n and 63
Step-by-step explanation:
the question belongs to arithmetic sequence and can be determined by the formula
= a1 + d (n-1)
Let " " represents the number of band members in the nth row
and 'd' represents the common difference.( as stated each row has 2 more band members than the row before it)
therefore, d=2
'a1' represents first row that has three members. So, a1 = 3
->Rule for nth term will be:
= 3 + 2(n-1)
= 3 + 2n -2
= 1+2n
-> In order to find total number of band members ''
Let represent total number in n rows
We'll use the formula, i.e = n/1 (
+
)
where, n is the number of terms, is the first term and
is the last term
So,
n=7
= 1 + 2(7)= 15
=> = 7/2 (3 + 15)
= 63
The total number of band members are 63