The correct answer is option 4 i.e. 7 : 8
⇒ 42−3+5222= a + √5b
On rationalizing the LHS part we get,
⇒ 42−3+5222= a + √5b
⇒ (42−3+5)(42−3−5222×(42−3−5)
⇒ 2(15−46)2(88−116−1110
Again on rationalization, we get,
⇒ (15−46)(88−116−1110×15+4615+46.