请教几道数学题

1,a magazine subscription is offered for 1 year at $12 or for 3 years at $29. if the rates do not change during the 3 years,the cost of a 3-year subscription is approximately what percent less than the total cost of 3 annual subscriptions?

2,on a legislative committee,the number of males is 2 fewer than twice the number of females.if one male was replaced by a female,there would be an equal number of males and females on the committee.how many members are on the committee?

3,If a motorist had driven 1 hour longer on a certain day and at an average rate of 5 miles per hour faster ,he would have covered 70 more miles than he actually did.How many more miles would he have covered than he actually did if he had driven 2 hours longer and at an average rate of 10miles per hour faster on that day?

1: 19%

2: xx=4,xy=6

3: 150

谢了