If the value of a gold coin is increased by 20% each year, find the percentage increase of the coin over three years.

Question

If the value of a gold coin is increased by 20% each year, find the percentage increase of the coin over three years.

Answer 1

suppose the coin has a value of $100

the first 20% increase is $20

the coin has a value of $120

the second increase of 20% is 0.2*$120=$24

the coin now has a value of $120+$24=$144

the third increase of 20% is 0.2*$144=$28.80

the coin now has a value of $144+$28.80=$172.80

the value went from $100 to $178.80

$178.80-$100=$78.80

78.8/100=78.8% increase