In August, Walton Bookstore must decide how many of next year$$s nature calendars to order.

Each calendar costs the bookstore $$7\mathrm{.}50$ and sells for $$10.$ After February $1,$ all unsold calendars

will be returned to the publisher for a refund of $$2\mathrm{.}50$ per calendar. Walton has examined

historical data and determined that demand follows the distribution given below. Walton want

to develop a simulation model to help decide how many calendars to order.

Demand Probability

$10030\%$

$15020\%$

$20030\%$

$25015\%$

$3005\%$