Question

B. The 100th term of 60, 110, 160, ... is (Simplify your answer.) How to do this?​

Answer 1

The 1st term is 60.

Add 50 to this to get the 2nd term, 60 + 50 = 110.

Add 50 to that to get the 3rd term, 110 + 50 = 160.

Add 50 to that to get the 4th term, 160 + 50 = 210.

And so on...

Notice that in the 2nd term, we added 1 copy of 50 to the 1st term.

In the 3rd, we ultimately added 2 copies of 50 to the 1st term.

In the 4th, we added 3 50s.

And so on... If the pattern continues, then the n-th term can be obtained by adding (n - 1) copies of 50 to the first term.

So, the 100th term is

60 + (100 - 1) * 50 = 5010