Find the percent increase. Round to the nearest percent. From 13 friends to 19 friends

The percent increase is %?

You can find the constant of proportionality by finding the ratio of

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.

One file clerk can file 10 folders per minute. a second file clerk can file 11 folders per minute. how many minutes would the two clerks together take to file 672 folders?