Percent increase, percent decrease and percent error

Answer Key - Grade 7 Math Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   After a growth spurt of 25%, Esme's bamboo plant is 60 centimeters tall. How tall was the plant before the growth spurt?

   48
2. 2.

   Jun lets out 20% more kite string, so the string is now 150 meters long. How long was the string before?

   125
3. 3.

   After 40% of the students went on a trip, 135 students are left at Noah's school. How many students were at the school before the trip?

   225
4. 4.

   Pia's band had 200 fans. The crowd grew by 20%, then shrank by 10%. How many fans are there at the end?

   216
5. 5.

   Ren's young tree is 60 centimeters tall. It grows by 50%, then a storm trims it by 20%. How tall is the tree at the end?

   72
6. 6.

   Tala's class has 150 pizza slices. 20% get eaten, then a delivery adds 50% more than what is left. How many slices are there at the end?

   180
7. 7.

   Ari's kitchen scale reads within 2% of the true mass. A bag's true mass is 250 grams. What is the largest reading the scale could show?

   255
8. 8.

   Jun's stopwatch is within 3% of the true time. The true time is 60 seconds. What is the smallest time it could show?

   58.2
9. 9.

   x is the number of bikes at Luz's school on Monday. By Tuesday the number goes down by 10%, then up by 30%. Which expression gives the number on Wednesday?

   • 0.9x
   • 1.2x
   • 1.17x
   • 1.3x
10. 10.

    x is the number of pages Milo read on day one. The next days it goes up by 40%, then down by 30%. Which expression gives the final number of pages?

    • 1.1x
    • 1.4x
    • 0.98x
    • 0.7x