Solve percent increase and percent decrease problems

Three times the difference of federico’s age, and 4, increased by 7, is greater than 37. what are possible values of federico’s age?

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)

What is the correct decimal form of 12%