Total earning of Ahmad is
Cost of the Large necklaces = Number of necklaces × Cost of one necklace
So the cost of large necklace = 3×4.7 = $ 14.10
In the same way cost of small necklaces =Number of necklaces × cost of one necklace
Therefore the cost of small necklaces = 5×3.9 = $ 19.50
So total earnings by selling necklaces will be = Earning from small necklaces + Earning from large necklaces
Total Earning of Ahmad = 14.10 + 19.50= $ 33.60