Question

he said to her how can you do this sum change into reported speech​

Answer 1

Answer: He told her how could he do that ?

Explanation:Here the above sentence is a interrogative sentence.so the conjunction or the joiner is not used here instead how when what where such words are used as conjunctions .as a result here ew have used how as our conjunction. next we have to change the pronoun from first person to third person .next we had change the word this to that which a rule regarding speech .so here we solved the problem of speech .hope it will help you. thanku