Sequence Problem? (1 Viewer)

[OH1995]

This is question 3a in chapter 6i of the year 11 cambridge 3 unit book, if it helps you to be able to look it up.

Use the formula T_n= a+(n-1)d to find the number of terms in this sequence
50+51+52+....+150
and then find the sum of the sequence. It's a pretty simple question but for some reason I am confused with finding the amount of terms with that equation.

Thanks!

 

[deswa1]

Its obvious that a=50 and d=1:
T(n)=50+(n-1)
150 (the last term)= 50+n-1
n=101
Therefore there are 101 terms

 

[barbernator]

T1=50
Tn=50+(n-1)
let Tk be the last term
Tk=50+(k-1)=150
k-1=100
k=101
therefore there are 101 terms in the series.

Im sure you can do the sum from here

dayyyum beaten

 

[deswa1]

dayyyum beaten

Soz . The next one can be yours

 

[OH1995]

Thanks for the help, I just got it after I posted

 

[barbernator]

Soz . The next one can be yours

all good. you can have the questions on BOS i'll have the ones next friday