The bill for dino's lunch was $19.45. he wanted to leave 20% of the total bill as a tip. how much should the tip be?

If tana tanb=k, show that(1+k)cos(a+b)=(1-k)cos(a-b)

Arestaurant offers a $12 dinner special that has 5 choices for an appetizer, 12 choices for an entrée, and 4 choices for a dessert. how many different meals are available when you select an appetizer, an entrée, and a dessert? a meal can be chosen in nothing ways. (type a whole number.)

It takes jonas 7 1/4 minutes to run the mile. it takes mario 8 5/12 to run the mile. how much faster is jonas than mario? 5/6 minute 1 1/3 minutes 1 1/6 minutes 1 1/2 minutesi will give points and brainlest