Question 259976
<pre><font size = 4  color = "indigo"><b>
That depends on how many consecutive integers you 
want to add to get 945. You forgot to tell us how 
many integers.  

For instance, is you had told us you wanted 10 consecutive integers
which have sum 945, we could have shown you how to find them.  
They would be

90+91+92+93+94+95+96+97+98+99 = 945

And, say, if you had told us the you wanted 18, then we'd
have said to start at 44

44+45+46+47+48+49+50+51+52+53+54+55+56+57+58+59+60+61=945

And, say, if you had told us the you wanted only 5 or 6, then we'd
have said to start at 187 if you wanted 5, and with 155 if you
had wanted 6

187+188+189+190+191=945

or with 6

155+156+157+158+159+160=945

or with just 2 consecutive integers, as the other tutor
assumed, it would be:

472+473=945.

We'd have use the equation

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

Suppose I had wanted to find five consecutive integers
whose sum is 945:

187+188+189+190+191=945

but didn't know I was supposed to start at 187.  Here's
how I'd know to start at 187:  I'd substitute {{{n=5}}}
{{{S[5]=945}}}

and {{{n=5}}} and {{{d=1}}} because the difference between
any two consecutive integers is 1.

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

{{{S[5]=5(2a[1]+(5-1)(1))/2}}}

{{{945=5(2a[1]+4)/2}}}

Multiply both sides by 2 to clear of fractions:

{{{1890=5(2a[1]+4)}}}

Divide both sides by 5

{{{378=2a[1]+4}}}

Subtract 4 from both sides

{{{374=2a[1]}}}

Then divide both sides by 2, and we'd have

{{{187=a[1]}}}

Then we'd have known to start at 187.

Next time you post on here, be sure to give all
the information and to tell us exactly what you 
want to find.

Edwin</pre>