LT

Test: Percentage change and interest

Dynamic tasks on discounts, repeated percentage changes, simple interest and financial choices. Also distinguishes percent from percentage points.

Question qty: 10
Duration in minutes: 25
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Time left: 00:00:00

Sample questions

  • An item cost kaina. A p% discount was applied. What is the new price?
  • An item cost kaina. Its price increased by p% in each of two consecutive years. What was the price after the second increase?
  • The price was kaina. It was first increased by p% and then decreased by p%. What is the final price?
  • A rate increased from buvo% to dabar%. By how many percentage points did it increase?
  • An item costs kaina. You may choose a p% discount or a fixed discount of nuolaida. Which saves more?
  • A student is saving for a purchase costing tikslas. The student has already saved p% of the required amount. How much more is needed?
  • After a p% discount, an item costs kaina. What was its original price?
  • A deposit of indelis earns p% simple interest per year. What will the balance be after metai years?

Percentage change and interest

To increase a quantity by p%, multiply by 1 + p/100; to decrease it, multiply by 1 − p/100. Successive changes are applied one after another, so equal percentage increases and decreases do not cancel.

Interest

Simple interest is calculated from the original principal. Distinguish the interest earned from the final amount. A percentage point is the difference between two percentage rates, not a relative percentage change.