Question

Evaluate the sum from n equals four to ten of quantity five n plus two.

202
207
254
259

Answer 1

The answer is D. 259

Explanation:

Step 1:
`\sum _(n=4)^(10)5n+2`

Step 2:
`\sum _(n=1)^(10)5n+2-\sum _(n=1)^35n+2`

Step 3:

`\sum _(n=1)^(10)5n+2=\sum _(n=1)^(10)5n+2-\sum _(n=1)^35n+2\\\sum _(n=1)^(10)5n+2=295`

`\sum _(n=1)^35n+2=\sum _(n=1)^35n+\sum _(n=1)^32=36\\`

Step 4:
`295-36=259`