When Klorina swims with the current, she swims 10 kilometers in 2 hours. Against the current she can swim only 8 km in the same time. How fast can Klorina swim in still water? What is the rate of the current?

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. when the check comes, it says they also need to pay $3.99 in sales tax. what percentage of the subtotal is the sales tax