The point charges used in the simulation are ± 1.0x10-9 c (nanocoulomb). if two such positive charges are placed 2.0 m away from each other, the force between them would be..

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )