Answer:
b. (0.035)(50,000) + (0.065)(31,500)
Step-by-step explanation:
Given, there is an interest of 3.5% on the first $50,000 in sales,
So, the earning for first sale = 3.5% of 50000 = 0.035(50,000)
Now,
Total amount of sale = $ 81,500,
Thus, the amount of second sale = $ 81,500 - $ 50,000 = $ 31, 500,
Here, there is an interest of 6.5% on second sale,
So, the earning in second sale = 6.5 % of 31, 500 = 0.065(31,500)
Hence, the total earning on both sales = 0.035(50,000) + 0.065(31,500)
Option 'b' is correct.