Write the explicit rule of the arithmetic sequence that has a first term of 3 and a fourth term of 18
1 answer:
Answer:
= 5n - 2
Step-by-step explanation:
The nth term of an arithmetic sequence is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Given a₄ = 18 , then
a₁ + 3d = 18 , that is
3 + 3d = 18 ( subtract 3 from both sides )
3d = 15 (divide both sides by 3 )
d = 5
Then
= 3 + 5(n - 1) = 3 + 5n - 5 = 5n - 2 ← explicit rule
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Percent of earnings that go to school = 80%
Percent of earnings that was spent on the fundraiser cost = 20%
Last year earnings were= $4000
80% of 4000 went to school which is =
20% of 4000 = went to costs.
a:
As given, this year, they want $4,000 to go directly to the school.
So let the earnings this year be represented by = x
As, 80% of the earnings go to school, so 80% of x = 4000
Hence, this year their earnings should be $5000 so that 80% of it which is $4000 will go to school. And 20% which is $1000 will go to costs.
Or we can say last year they earned $4000, so this year they need to earn $1000 more.
b:
The total amount they need to earn this year is $5000.