Answer:
1. 900
2. 50 dollars
3. 6 weeks
4. 300 dollars
5. 75 dollars
1. when the number of weeks are at 0, the money she has in her account is 900. So, she has 900 dollars in her account at the beginning.
2. she starts off with 900. The next week, she has 850 in her account, then 800, and so on. therefore, she spends 50 dollars a week.
3. 1/3 times 900 is 300, so she needs to spend 300 dollars. 300/50 is 6, so it will take her 6 weeks to spend 300 dollars.
4. If she spends 50 a week over 12 weeks then multiply 50 and 12. You get 600. we know she starts with 90p, so 900-600 is 300. she spends 600 and ends up with 300 in 12 weeks.
5. we know she spends 50 a week. 50 times 1.5 is 75, so hee brother spends 75 dollars a week