Answer and Explanation:
The computation of the payback period for each product line is as follows
                                 (in dollars)
Year Liquid Soap    Cumulative   Body lotion   Cumulative
1       170,000             170,000        90,000          90,000
2      150,000             320,000      90,000          180,000
3      120,000             440,000      90,000          270,000
4      100,000             540,000      90,000         360,000
5      70,000               610,000       90,000        450,000
6      40,000               650,000     90,000          540,000
7      40,000               690,000     90,000          630,000
8     30,000                720,000     90,000         720,000
So, the Payback period for Liquid soap is 4 years and Payback Period for Body Lotion is 6 Years  respectively
Therefore we suggest liquid soap as it contains better paypack period as compared with the body lotion