Considering that individual 6 songs each $0.99 will cost Martha a total of 6*$0.99=$5.94 and also individual 3 songs for $1.29 will mean he incurrs a sub-total cost of 3*1.29=$3.87
Total cost of buying 9 individual songs will be C=5.94+3.87=$9.81 which is less than the cost of the whole album. Therefore, it is recommended to buy individual songs instead of album for this case since the total cost of individual songs that the buyer is interested in is less than the total cost of an album
