Question 1084070
<pre>
96+94+92+ ...  to 22 terms:

a<sub>1</sub> = 96, n = 22, d = -2

{{{S[n]=expr(n/2)*(2a[1]+(n-1)d^"")}}}

{{{S[22]=expr(22/2)*(2(96)+(22-1)(-2)^"")}}}

{{{S[22]=11*(192+(21)(-2)^"")}}}

{{{S[22]=11*(192+(-42)^"")}}}

{{{S[22]=11*(192-42)^"")}}}

{{{S[22]=11*(150)^"")}}}

{{{S[22]=1650)}}} chairs

Edwin</pre>