Question

Which term of the sequence `20,19 1/4, 18 1/2, 17 3/4,...` is the first negative term?

Answer 1

`a=20,d=-3/4`
`a_n=a+(n-1)d`
`a_n=20+(n-1)*(-3/4)`
`20+(n-1)*(-3/4)<0`<br> `(20*4+(n-1)(-3))/4`
`80-3n+3<0`<br> `83<3n`<br> `n>83/3`
`n>27.66`
`n=28`.