Bill thought he bought 70 chihuahuas, but some of them turned out to be rats. If the number of rats was 6 times the number of chihuahuas, how many rats did he buy? Give the rationale and then the answer.
Let's think step by step. Let r be the number of rats and c be the number of real chihuahuas. We know that r + c = 70 and r = 6c. Substituting the second equation into the first equation, we get 6c + c = 70. Combining like terms, we get 7c = 70. Dividing both sides by 7, we get c = 10. Substituting this back into r = 6c, we get r = 10 * 6 = 60.. The answer is: 60.

Damien jogs 5 miles per day on weekdays only. How many miles does he run over three weeks? Give the rationale and then the answer.
Let's think step by step. Three weeks at 5 days per week means Damien runs 3 * 5 = 15 times in three weeks. If each time he runs 5 miles, then over 15 running days he covers 5 * 15 = 75 miles.. The answer is: 75.

Emma buys 2 containers of milk every school day for lunch. She does not go to school on the weekends. How many containers of milk does she buy in 3 weeks? Give the rationale and then the answer.
Let's think step by step. There are 5 school days in a week: 5 days / week x 2 containers of milk / day = 10 containers of milk every week. Finally the number of container for 3 weeks is 3 weeks x 10 containers / week = 30 containers.. The answer is: 30.