Old Faithful, a famous geyser in Yellowstone National Park, erupts approximately once every 77 minutes. (It used to erupt more frequently, but earthquakes have changed the geyser’s plumbing, so it’s not letting off a little steam as often as it used to.) Assuming that it spurts 8000 gallons of water each time, how many gallons will Old Faithful spurt in one year?

*There are 365 × 24 × 60 = 525,600 minutes in a year, so the geyser will erupt 525,600/77 = 6825 times per year, approximately. This makes a total of 8000 × 6825 = ***54,600,000*** gallons spurted by Old Faithful per year. *

Predicting when Old Faithful will spurt *next* can be done by timing the previous eruption. If an eruption lasts *t* minutes, the next eruption will occur in approximately 12.5*t* + 33 minutes. If a 4-minute eruption begins at 11:23 a.m., at what time would you expect the next eruption to occur?

*The eruption begins at 11:23 a.m., so it ends at 11:27 a.m. The next eruption should occur in 12.5(4) + 33 = 83 minutes (1 hour, 23 minutes). So, it will likely happen at about ***12:50 p.m.**

Old Faithful is just one of hundreds of geysers in Yellowstone National Park. Yellowstone is a large park consisting of 3472 square miles of land. Of this land, 91% is in Wyoming, 7.6% is in Montana and 1.4% is in Idaho. How many square feet of Yellowstone is located in Idaho?

*There are 5280 ^{2} square feet in a square mile, so there are 5280^{2} × 3472 × 0.014 = *

**1,355,113,267.2***square feet of Yellowstone land in Idaho.*

**♦**** ****Page 1**** of the linked PDF contains PROBLEMS & SOLUTIONS. **

**Page 2 contains ONLY PROBLEMS. ♦**