How do I solve for the variables r, s, and t

Your long distance telephone provider offers 2 plans. plan a has a monthly fee of $15 and $0.25 per minute. Plan b has a monthly fee of $20 and $0.05 per minute.

A rock band has 5 members, and 2/5 of the members play string instruments. Also, 0.4 of the members sing. Does the band have the same number of the string instrument players as singers? Explain

A brownie recipe asks for tow and one third times as much sugar as chocolate chips. If three and one half cups of sugar is used, what quantity of chocolate chips would then be needed, according to the recipe

Solve. Show your work.: A card traveled a distance of 124 miles in 2.5 hours. Find the speed of the car.

What the vaule of x in the equation 3x-4y=65, when y = 4

Ashton left his house and ran 4 miles east and 3 miles north he took the diagonal path back home if he burned 105 calories every mile that he ran how many total calories did he burn on this run

Solve 3x-5y=13 4x+8y=-9

Lewis needs 1/8 quart of paint to cover 10 square yards. How many square yards can he paint with 4 quarts of paint?

It is recommended that you have 8 servings of water per day. A serving of water is about 237 mL. If Carmelo drank 7 servings, about how many liters of water did he drink?

What is 5,000 in scientific notation?