It looks is from the people that said that
We have to find when she will accumulate $175. If she saves $5 more for each month, then in the following months she will save 15, 20, 25 and so on. We can generalize this sequence as 10 + 5(n-1), where n is the number of the months. Applying the sum of nth formula of algebraic sequence, we can write



The correct answer is 7 months. We can check that for seven months she will save 15, 20, 25, 30, 35, 40 and including the first 10 dollar will sum up to 175 dollars.
most likely so that he wouldn't fall in.