百分率增减・折扣与复合变化

The percent increase in mass of a certain red kangaroo from 80 days old to 160 days old was 676%. If this red kangaroo's mass was k grams at 80 days old, which expression represents its mass, in grams, at 160 days old?

A business owner plans to purchase the same model of chair for each of the 81 employees. The total budget to spend on these chairs is $14,000,which includes a 7% sales tax. Which of the following is closest to the maximum possible price per chair, before sales tax, the business owner could pay based on this budget?

The number a is 60% greater than the positive number b. The number c is 45% less than a. The number c is how many times b?

The value of a toy increased by 193% from the end of 2016 to the end of 2017 and then decreased by 31% from the end of 2017 to the end of 2018. What was the net percentage increase in the value of the toy from the end of 2016 to the end of 2018?

The regular price of a shirt at a store is $11.70. The sale price of the shirt is 80% less than the regular price, and the sale price is 30% greater than the store's cost for the shirt. What was the store’s cost, in dollars, for the shirt? (Disregard the $ sign when entering your answer. For example, if your answer is $4.97, enter 4.97)

The value of an autographed baseball increased by 173% from the end of 2013 to the end of 2014 and then decreased by 18% from the end of 2014 to the end of 2015. What was the net percentage increase in the value of the autographed baseball from the end of 2013 to the end of 2015?

A clothing store buys shirts at a wholesale price of 4.00 dollars each and resells them each at a retail price that is 280% of the wholesale price. At the end of the season, any remaining shirts are marked at a discounted price that is 80% off the retail price. What is the discounted price of each remaining shirt, in dollars?

A gift shop buys souvenirs at a wholesale price of 7.00 dollars each and resells them each at a retail price that is 290% of the wholesale price. At the end of the season, any remaining souvenirs are marked at a discounted price that is 80% off the retail price. What is the discounted price of each remaining souvenir, in dollars?

A researcher investigated two species of mites: a predator and its prey. At the start of a week, there was an equal number of the two species. At the end of the week, the number of prey had increased by 2100% of the number of prey at the start of the week, and the number of predators had increased by 450% of the number of predators at the start of the week. The number of predators at the end of the week was p% less than the number of prey at the end of the week. What is the value of p?

A researcher investigated two species of mites: a predator and its prey. At the start of a week, there was an equal number of the two species. At the end of the week, the number of prey had increased by 2,700% of the number of prey at the start of the week, and the number of predators had increased by 180% of the number of predators at the start of the week. The number of prey at the end of the week was p% greater than the number of predators at the end of the week. What is the value of p?

The price of an item increased by p% from $18 to $21. What is the value of p?