Question 1122062
inverse proportion formula is y = k / x


when you say that the the weight of a person varies inversely with the square of the distance from the center of the earth, the formula becomes:


w = k / d^2


when w = 90 and d = 4000, the formula becomes 90 = k / 4000^2.


solve for k to get k = 90 * 4000^2 = 144 * 10^7.


when the person is 160 miles above the surface of the earth, the person is 160 + 4000 = 4160 miles from the center of the earth.


the formula then becomes y = k / d^2 which becomes y = 144 * 10^7 / 4160^2.


solve for y to get y = 83.21005917.


that should be your answer.