1) Three numbers which are co-prime to one another are such that the product of the first two is 551 and that of the last two is 1073 .The sum of three numbers is A) 75 B) 81 C) 85 D) 89 E) 90 Answer: Option CExplanation:Let the numbers be x,y,z which are prime to one another Xy = 551 yz = 1073 Y = HCF of 551,1073 = 29 $x=\frac{551}{29}=19$ $z=\frac{1073}{29}=37$ Sum of the numbers = 29+19+37 =85