1/4 of the trees are peach trees. This is because 48 + 30 + 42 (because we need to find out the total number to trees for the denominator) = 120. Therefore, we have the fraction: 30/120. To simplify, we need to find the greatest common factor, which is 30. Therefore, dividing 30 to both top and bottom, we get 1/4. I hope this helps! :D