Sir, - The reported drop in the number of students enrolled this year at primary and secondary levels would seem to offer an idealopportunity to reduce pupilteacher ratios at both levels at little or no extra cost.The size of the "sea of faces" in front of a teacher has a fundamental bearing on the educational outcome for a class.If the improved pupil-teacher ratio was used strategically to help weaker students it would do something practical to create equality of opportunity in education. - Yours, etc.,Jim Cooke,Rathfarnham,Dublin 16.