A 73-year-old Indian farmer who vowed not to marry before passing his high school exams has failed to get through for the 38th time.

Shiv Charan Yadav has been taking the exams -- normally given to schoolchildren at the age of 15 -- every year since 1969, without success.

He was in his 30s when he first decided to better himself through education.

This year, he failed everything except Sanskrit, scoring only 103 out of a possible 600 points.

He said he found mathematics especially hard, blaming the subject for dragging down his score.

"Once I pass I want to get married to a girl who's under 30," Yadav, who lives alone in Kohari village in the western desert state of Rajasthan, told Reuters.

He is now revising for his 39th attempt next year.