Word Problem

[Magdy101]

If a person earns 20 dollars on day one and on the next day he earns half, i.e 10 dollars and the third day 5 dollars; how many days will it take him to reach a total of 40 dollars earned.

 

[Dr.Peterson]

What are your thoughts? Have tried, for example, making a table of values to see what happens?

Or do you know anything about geometric series, rather than just arithmetic?

 

[HallsofIvy]

My first thought would be that "total" MEANS "add". It's tedious but you can just add! The fourth day he makes 2.50 dollars, the fifth day, 1.25 dollars. But what about the sixth day? Half of 1.25 is 0.625. Is that reduced to 0.62 or increased to 0.63? Honestly I wouldn't even worry about that! For the first 5 days we have 20+ 10+ 5+ 2.50+ 1.25= 38.75. The sixth day, we add half of 1.25 which is 0.625. 38.75+ 0.625= 39.375, not quite 40. Half of 0.625 is 0.3125 which gets us up to 39.6875. Continue to see IF you ever get past 40 and if you do stop there!