比・比例・速率与单位换算

Before liftoff, one of a space shuttle's solid rocket boosters contained 489,000 kilograms (kg) of propellant. Exactly 23 seconds after liftoff,374,046 kg of this propellant remained.On average, how much propellant, in kg, did this solid rocket booster burn each second after liftoff?

The ratio x to y is equivalent to the ratio 7 to 9. If x = 10t, what is the value of y in terms of t ?

The ratio of the base to the height of a triangle is 1 to 8. The base of the triangle is 216 centimeters. What is the height, in centimeters, of the triangle?

The area of a rectangular region is increasing at a rate of 300 square centimeters per hour. What is this rate, in square meters per minute? (1 meter =100 centimeters)

How many centimeters are equivalent to 47 meters? (1 meter = 100 centimeters)

One gallon of sealant costs $29 and will cover 300 square feet of a surface. A deck has a total surface area of d square feet. Which equation represents the cost c, in dollars, of the sealant needed to cover the deck twice?

An area of 56.00 square nautical miles is equivalent to k square kilometers. To the nearest tenth, what is the value of k? (1 nautical mile = 1.852 kilometers)

An object's speed is increasing at a rate of 10.5 meters per second squared. What is this rate, in miles per minute squared, rounded to the nearest tenth? (Use 1 mile = 1,609 meters.)

A 9-pound cat eats two types of canned cat food: chicken-flavored and duck-flavored. The recommended amount of chicken-flavored food is 2.25 cans per 8 pounds of a cat's weight per day. The recommended amount of duck-flavored food is 0.75 cans per 5 pounds of a cat's weight per day. If c is the number of chicken-flavored cans and d is the number of duck-flavored cans a 9-pound cat eats in one day, which equation describes all the possible values of c and d for the cat to eat the recommended amount of food based on its weight?

The speed of a white-throated needletail, a type of bird, in flight was measured to be 79 miles per hour. What was the white-throated needletail's measured speed, in kilometers per hour? (Use 1 mile = 1.6 kilometers.)

Gentoo penguins are the fastest swimming-underwater birds. A gentoo penguin was recorded swimming at a rate of 7 meters per second for 160 meters. For approximately how many seconds was the penguin recorded swimming at this rate?

An object's speed is increasing at a rate of 9.4 meters per second squared. What is this rate, in miles per minute squared, rounded to the nearest tenth? (Use 1 mile = 1,609 meters.)