Melanie has decided to run for president of her science club. She would like to purchase colorful rubber bracelets that say, “Melanie for President!” She plans to pass out these colorful bracelets at the next meeting. There are twenty bracelets in each package. Each bracelet costs $3.50. How much will Melanie have to pay if she purchases two packages of colorful bracelets?

Melanie will have a total of 40 bracelets if she purchases two packages (20 bracelets per package x 2 packages = 40 bracelets).

The cost of one bracelet is $3.50, so the cost of 40 bracelets would be:

40 bracelets x $3.50/bracelet = $140

Therefore, Melanie will have to pay $140 if she purchases two packages of colorful bracelets.

To calculate the total cost of purchasing two packages of colorful bracelets, we need to multiply the cost of each package by the number of packages.

The cost of each package is $3.50.

Melanie wants to purchase two packages, so the calculation is:

$3.50 x 2 = $7.00.

Therefore, Melanie will have to pay $7.00 if she purchases two packages of colorful bracelets.