Given :
We have $100 in our saving account and plan to deposit $12.50 each month.
Cost of 10 acres of land in mars is $175.
To Find :
How many months will it take you to save enough money to buy 10 acres of land on Mars.
Solution :
Let, after n months amount in account is :

This A should be greater than equal to $175.
A ≥ 175
100 + 12.50n ≥ 175
n ≥ 75/12.50
n ≥ 6
Therefore, it will takes 6 months to collect such amount.