1) 10.5 = 10 1/2 = 21/2 ounces in bottle
2) 21/2 * 1/16 = 21/32 ounces one use
3) 21/32 * 6 = 63/16 ounces six use
4) 21/2 - 63/16 = 168/16 - 63/16 = 105/16 = 6 9/16 ounces left
[tex]6\frac{9}{16}[/tex] fluid ounces
First, we are going to find the total amount of shampoo he used. We know from a our problem that he uses [tex]\frac{1}{16}[/tex] of the shampoo every time he washes his hair and he washed his hair 6 times, so we just need to multiply the number of times (6) by the amount used every time ([tex]\frac{1}{16}[/tex]) to find how much shampoo he used:
[tex]6*\frac{1}{16} =\frac{6}{16} =\frac{3}{8}[/tex]
We know that he used [tex]\frac{3}{8}[/tex] of the bottle of shampoo. Since the bottle of shampoo held 10.5 fluid ounces, we are going to multiply 10.5 fluid ounces by [tex]\frac{3}{8}[/tex] to find how much fluid ounces he used:
[tex]10.5f.oz*\frac{3}{8} =3.9375f.oz[/tex]
Now, to find the ounces of shampoo left, we just need to subtract the ounces used (3.9375 fluid ounces) by the initial fluid ounces in the bottle of shampoo (10.5 fluid ounces):
[tex]10.5f.oz-3.9375f.oz=6.5625f.oz[/tex] or expressed as a mixed fraction: [tex]6\frac{9}{16} f.oz[/tex]
We can conclude that there are [tex]6\frac{9}{16}[/tex] fluid ounces of shampoo left after Tomas washed his hair 6 times.
