The density of an object is the qoutient of its mass and its volume

Taking algebra two apex courses and need with these questions

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

Avery’s piggy bank has 300 nickels, 450 pennies, and 150 dimes. she randomly picks three coins. each time she picks a coin, she makes a note of it and puts it back into the piggy bank before picking the next coin.