Can someone please help me with these?

You make and sell triangular flags. each flag has a base of  3.53.5  feet and a height of  2.52.5  feet. fabric for the flags costs  $0.40$0.40  per square foot. what is the cost to make one flag?

In the sixth grade 13 out of 20 students have a dog if there are 152 sixth grade students how many of them have a dog

Aaron invested a total of $4,100, some in an account earning 8% simple interest, and the rest in an account earning 5% simple interest. how much did he invest in each account if after one year he earned $211 in interest? select one: a. $200 at 8%, $3,900 at 5% b. $3,200 at 8%, $900 at 5% c. $900 at 8%, $3,200 at 5% d. $3,900 at 8%, $200 at 5%