The original price of the computer is $489. The computer is discounted 30%, which means that 30% of the price is removed from the original price.
30% of 489 is
489 * 0.3 which is $146.7
146.7 is the discounted amount, not the selling price. To find the selling price, subtract how much is discounted ( 146.7) from the original price (489).
Lines that intersect are intersecting or crossing lines. Perpendicular lines are lines that cross at a 90 degree angle. Skew lines are lines that are non-coplanar and don’t intersect.
The average is (time)/(number of problems)=(45/60)/20=(3/4)/20=3/80 hours per problem. In minutes, the answer would be 3/80*60=9/4 minutes per problem.