Help please I must be missing something on this question:

When the price of candy bars decreased from $0.80 to $0.75, the quantity demanded changed from 4,000 per day to 4,500 per day. In this price range, the price-elasticity coefficient (based on the midpoint formula) for candy bars is:

I am coming up with $1.82

but the answers given is 1.2, 2.5, .55, 1.63

Thank you