One year on Mercury is equal to 87.97 Earth days. One year on Pluto is three times the length of one Mercury year minus 16.21 days. How long is one year on Pluto? Sorry it is a bit long but I wished to explain about ambiguities in the question and the derivation of units/equations. The actual calculations are short! With assumptions I get ## ~~ 0.69color(white)(.) “Earth years”##
