Question

Every year Beth doubles the amount of money she donates to charity. She

donated $1 to charity at age 10.
How much money will she donate at age 20?
A. $21
B. $41
C. $512
D. $1,024

Answer 1

Answer:1,024

Explanation:

1*2=2 11yrs

2*2=4 12yrs

4*2=8 13yrs

8*2=16 14yrs

16*2=32 15yrs

32*2=64 16yrs

64*2=128 17yrs

128*2=256 18yrs

256*2=512 19yrs

512*2=1,024 20yrs

Answer 2

D

Explanation:

l = a * r ^ (n - 1)

n = 11

a = 1

r = 2

L = 1 * 2^(11 - 1)

L = 2^ 10

L = 1024