Tim is choosing between two cell phone plans that offer the same amount of free minutes. Cingular's plan charges 39.99 per month with additional minutes costing .45. Version plan costs 49.99 with additional minutes at .40. How many additional minutes will it take for the plans to cost the same

Get the cheapest one

The answer is 153.37 lb

The weight (w) of a person on or above the surface of the earth varies inversely as the square of the distance (d²) the person is from the center of the earth:
w = k/r²
w * d² = k

w1 * d1² = k
w2 * d2² = k

w1 * d1² = w2 * d2² = k

We know:
On the Earth:
w1 = 180 lb
d1  = 3900 mi
Above the Earth
w2 = ?
d2 = 3900 + 325 = 4225 mi (we must add the total distance from the center of the Earth).

w1 * d1² = w2 * d2² 
w2 = w1 * d1² / d2² 
w2 = 180 * 3900² / 4225²
w2 = 180 * (3900/4225)²
w2 = 153.37 lb