Need an explanation of how to calculate this question. I am not sure how to allocate when there are three products

given:

Product	Selling Price
Do	$8
Ra	$7
Mi	$5
Do + Ra	$13.50
Do + Mi	$11.50
Ra + Mi	$10.50
Do + Ra + Mi	$17.00

It Song Company uses the incrementalrevenues allocation method and has designated Ra as the primary product, the amount of reyenues from a bundled package of all three products to be allocated to Ra would be a. 55.95. b. 54.00. c. 58.00. d. 57.00. If Song Company uses the incrementalrevenues allocation method and has designated Ra as the primary product and Do as the first incremental product, the amount of revenues from a bundled package of all three products to be allocated to Mi would be a. 55.00. b. 52.00. c. 54.25. d. 58.00