The total number of hours that Rafael has worked by Tuesday is 8+10 = <<8+10=18>>18 hours.
To complete his assigned work hours, Rafael works 20 hours more, making his total weekly hours to be 18+20 = <<38=38>>38 hours.
Since he is paid $20 per hour, he makes $20*38 = $<<20*38=760>>760 a week.
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