Let us convert all figures into decimals so that we can compare them easily.
Monday 0.3
Tuesday 15% = 0.15
Wednesday 1/6 = 0.1666
Thursday 0.2
Friday 1/8 = 0.125
Clearly, I spent the least amount of time on Friday using IT and the time is 0.125 or 1/8.
Point +10.
(-2)*(-1) gives +2 (a negative number multiplied for another negative gives a positive number).
2*5 = +10
A taco costs $5
This is because there was no difference in the cost except for $5. The only item added was one taco. Drinks cost $2 each.
A little more info please?