The formula for calculating the percent change in a value between two points in time is:
p = (N - O)/O * 100
Where:
p is the percent change - what we are solving for in this problem.
N is the New Value - 7 pounds in this problem.
O is the Old Value - 12 pounds in this problem.
Substituting and solving for p gives:
p = (7 - 12)/12 * 100
p = -5/12 * 100
p = -500/12
p = 41.7 rounded to the nearest tenth.
Phil's weight changed color(red)(-41.7%) during hibernation.
To gain his weight back Phil would go from 7 pounds (this is now the Old Value) to 12 pounds (this is now the New Value).
Substituting these values into the formula gives:
p = (12 - 7)/7 * 100
p = 5/7 * 100
p = 500/7
p = 71.4 rounded to the nearest tenth.
Phil would need to add color(red)(71.4%) of his weight to get to the weight he was before hibernating.
