Sum of a finite geometric series, and infinite geometric series

Answer Key - Grade 11 Math Worksheet - Challenge Me

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

1. 1.

   Milo works out Σ from k = 1 to 5 of 5 · 3^k for math club. What is the sum?

   1815
2. 2.

   Noah works out Σ from k = 1 to 6 of 64 · (1/2)^k for math club. What is the sum?

   63
3. 3.

   Pia works out Σ from k = 3 to 7 of 2 · 3^(k − 1) for math club. What is the sum?

   2178
4. 4.

   Ren reads on a math club card that an infinite geometric series has total 36 and ratio 1/4. What is its first term?

   27
5. 5.

   Zee reads on a math club card that an infinite geometric series has total 60 and ratio -1/2. What is its first term?

   90
6. 6.

   Ari reads on a math club card that an infinite geometric series has total 45 and ratio -1/3. What is its first term?

   60
7. 7.

   Bo watches the gym teacher drop a soft play ball from 9 feet. Each bounce rises 2/5 of the height before. If it bounced forever, how many feet would it travel up and down?

   21
8. 8.

   Esme watches the gym teacher drop a bouncy ball from 8 feet. Each bounce rises 3/4 of the height before. If it bounced forever, how many feet would it travel up and down?

   56
9. 9.

   Jun drops a rubber bouncy ball from 5 feet, and each bounce rises 4/5 of the height before. If it bounced forever, how many feet would it travel up and down?

   45
10. 10.

    Kira drops a bouncy ball from 4 feet, and each bounce rises 3/4 of the height before. If it bounced forever, how many feet would it travel up and down?

    28