How do I add and subtract fractions?

The perimeter of a rectangle is aboiut 11.9cm. if you double the width of the rectangle the perimeter is about 15.8 cm. find the dimensions of the smaller rectangle. Round the given values to the mearest integer.

A 3-gallon cylindrical water container has a height of 1.5 feet and a radius of 3.5 inches. Nate fills up a 2-gallon jug from the container before going on a hike.

The sum of a number 9 is multiplied by - 2 and the answer is - 8 find the number.

Which algebraic expression represents the phrase " the quotient of negative right and the sum of a number and three"?

On a winter morning the temperature before sunrise was - 11 f. the temperature then rose by 1/2 degree each hour for 7 hours before dropping by 2 1/4 degrees each hour for 3 hours. what was the temperature in degrees Fahrenheit after 10 hours

The nickels and dimes all fell on the floor. There were 12 more nickels than dimes, and the total value of the coins was $5.10. How many nickels and how many dimes were on the floor?

2. mrs. barlow's math class took a test yesterday. out of 70 students, 70% of them passed. how many of mrs. barlow's students passed the test?

A lunch counter sells two types of sandwiches, roast beef and chicken salad. The profit on the sandwiches is $2 for chicken salad and $3 for roast beef. The amount of bread available is enough for 30 sandwiches.

Evaluate the following expression 40 - 8 - 102

The value of a computer is $1200. It loses 20% of its value every year. Write a function the represents the value y (in dollars) of the computer after t years. The find the value of the computer after 5 years.