Heather solved this problem:

75 is 300% of what number?

A tape diagram. StartFraction part Over whole EndFraction = StartFraction 300 Over 100 EndFraction = StartFraction 75 Over question mark EndFraction. StartFraction part Over whole EndFraction = StartFraction 75 times 4 Over 100 times 4 EndFraction = StartFraction 300 Over 400 EndFraction

What error did Heather make?