 |
| ||
| |||
|
| Math Central | Quandaries & Queries |
|
Question from Abbi: hi there im a student in 11 grade ive been trying to do this task but i have no idea how to do it |
Hi,
I think the problem says
the first term is 4 and the sum of the first twenty terms is 1030
If the common difference is $d$ then here are a few of the terms
| first term | second term | third term | ....... | twentieth term |
|---|---|---|---|---|
| $4$ | $4+d$ | $4+2d$ | ..... | $4+19d$ |
The sum of these terms is 1030 so
\[4 + (4+d) + (4+2d) + \cdot \cdot \cdot + (4 + 19 d) = 1030.\]
which simplifies to
\[20 \times 4 + d(1 + 2 + \cdot \cdot \cdot + 19) = 1030.\]
Solve for $d.$
Penny
| ||
| ||
| ||
 |
 |
|
Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.