A store displays seven computers on a shelf side–by–side. Find the total length of the computers on the table if the first computer was six inches wide and the width of each successive computer is three inches longer than the previous one.

Question

anonymous · Answer

I got sigma top= 7 bottom= i = 1 and the formula being 6+3i is that correct?

anonymous · Answer

If i = 1, wouldn't your first computer be 9 inches long. 

Anyhow, I came up with this equation.

$$6n + (n-1)(3)$$  Where n = the number of computers.

With an answer of 60 inches.

anonymous · Answer

6+9+12+15+18+21+24

Is not 60.

anonymous · Answer

kirihara, the formula is correct except for the point that marshall made; it needs to be sum of 6+(3(i-1)) for i = 1 to 7.

anonymous · Answer

Thanks for the correction.