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Yes it is possible to achieve your requirement. If you add a quantity option in your form, it will automatically change the total price. You will have to display the total price in form. Please check the screenshot below:
The following guide should help you on how to add options in payment question: https://www.jotform.com/help/225-How-to-add-options-to-Payment-Forms
In case if you want the product pricing to change dynamically based on quantity ot any other option, you may also like to check the following guide on how special pricing works: https://www.jotform.com/help/265-What-is-Special-Pricing
Hope this answers your query.
Do try it out and get back to us if you have any trouble.