The total area under the normal distribution curve is 1 or 100%. The figure shows that 99.7% of the buyers paid prices in the range $17,000 to $29,000. Therefore a total of 0.3% of the buyers paid prices below $17,000 and above $29,000. The normal distribution is symmetrical. Therefore the percentage of buyers who paid more than $29,000 is 0.3/2 = 0.15%.