Write an algebraic expression for this: the quotient of triple a number decreased by threety

You eat 8 strawberries and your friend eats 12 strawberries from a bowl. there are 20 strawberries left. which equation and solution give the original number of strawberries?

If 10 men take 18 days to mow 60 acres of grass, how long will 15 men take to mow 80 acres?

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?