Answer:
His total earning for 10 miles is $ 140.
Explanation:
Given,
He earns for first miles = $ 5,
Since, he earns an additional $7 for the second mile, an additional $9 for the third mile, and so on
That is, his earning for second miles = $ 7,
For third miles = $ 9,
For fourth miles = $ 11 ,
..............So, one...
So, we get a sequence,
5, 7, 9, 11, ..........
Which is an A.P.
Having first term, a = 5,
common difference, d = 2,
Number of terms, n = 10
Thus, the sum of the A.P. is,
![S_n=(n)/(2)[2a+(n-1)d]](https://img.qammunity.org/2019/formulas/mathematics/middle-school/zlxdeh4y1z86kc1buiv5zlr8j0r6ep4dw7.png)
[tex]S_{10}=\frac{10}{2}[10+18]=5\times 28 = 140/tex]
Hence, His total earning for 10 miles is $ 140.