Question

Bank account starts with $10 and doubles each week.Bank account D starts with $1000 and grows by $500 each week.

When will account c contain more money than account D.
0 weeks
3 weeks
9 weeks
11 weeks
15 weeks
89 weeks

Answer 1

9 weeks

Explanation:

set y as how much money they have

set x as how many weeks spend

Bank account C:

y = 10 * 2^x

Bank account D:

y = 1000 + 500x

Set this two equations equal to find the point of two bank account have the same amount of money:

10 * 2^x = 1000 + 500x

Solve the equation:

2^x = 100 + 50x