Answer:

Assuming the coffee break is instant and he goes right back to his project,

that's 9 1/2 divided by 1 1/2

as improper fractions that's

19/2 divided by 3/2

reciprocal and multiply

19/2 x 2/3

19x2 / 2x3

38/6

Simplify:

19/3

or

6 1/3

or that could be only 6 before he's finished

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