‘How →amuch time →bdid Rahman and Sultan →chad to do the experiment before they →dobtained the results they→e had been expecting?

Question

‘How →amuch time →bdid Rahman and Sultan →chad to do the experiment before they →dobtained the results they→e had been expecting?

Accepted Answer

সঠিক উত্তর: c। ব্যাখ্যা:

$‘ H o w \to_{a}^{m u c h} t i m e \to_{b}^{d i d R a h m a n a n d S u l \tan} \to_{c}^{h a d} t o d o t h e e x p e r i m e n t b e f o r e t h e y \to_{d}^{o b t a i n e d t h e r e s u l t s} t h e y \to_{e}^{h a d b e e n e x p e c t i n g ?}$