Arithmetic sequences

9000064805

Level: 
C
The sides of a box form three consecutive terms of an arithmetic sequence. The volume of the box is \(665\, \mathrm{cm}^{3}\). The shortest side is \(5\, \mathrm{cm}\). Find the surface area of the box.
\(501\, \mathrm{cm}^{2}\)
\(315\, \mathrm{cm}^{2}\)
\(615\, \mathrm{cm}^{2}\)
\(805\, \mathrm{cm}^{2}\)
\(1\: 215\, \mathrm{cm}^{2}\)

9000065301

Level: 
A
Find the recurrence equations for the arithmetic sequence with the first term \(a_{1} = 4\) and the common difference \(d = -2\).
\(a_{1} = 4;\ a_{n+1} = a_{n} - 2,\ n\in\mathbb{N}\)
\(a_{1} = 4;\ a_{n+1} = a_{1} - 2,\ n\in\mathbb{N}\)
\(a_{n} = 4 + a_{n+2},\ n\in\mathbb{N}\)
\(a_{n+1} = a_{n} + 2,\ n\in\mathbb{N}\)

9000065302

Level: 
A
Find the formula for the \(n\)-th term of an arithmetic sequence with the first term \(a_{1} = 1\) and the second term \(a_{2} = -2\).
\(a_{n} = 4 - 3n,\ n\in\mathbb{N}\)
\(a_{n} = 1 - 2n,\ n\in\mathbb{N}\)
\(a_{n} = -2 + n,\ n\in\mathbb{N}\)
\(a_{n} = 3 + 2n,\ n\in\mathbb{N}\)

9000065303

Level: 
A
Find the recurrence equations for the arithmetic sequence with the second term \(a_{2} = 7\) and the common difference \(d = 4\).
\(a_{1} = 3;\ a_{n} = a_{n-1} + 4,\ n\in\mathbb{N}\)
\(a_{1} = 7;\ a_{n+1} = a_{n} + 4,\ n\in\mathbb{N}\)
\(a_{n} = 7 + a_{n+4},\ n\in\mathbb{N}\)
\(a_{n+1} = a_{n} + 7,\ n\in\mathbb{N}\)