Three numbers which are co-prime to each other are such that the product of the first two is 551 and that of the last two is 1073. The sum of the three numbers is:

Answer: Option C

Since the numbers are co-prime, they contain only 1 as the common factor.
Also, the given two products have the middle number in common.
So, middle number = H.C.F. of 551 and 1073 = 29
$$\begin{array}{rl}& \text{First}\text{number}\\ & =\frac{551}{29}\\ & =19\\ & \text{Third}\text{number}\\ & =\frac{1073}{29}\\ & =37\\ & \therefore \text{Required}\text{sum}\\ & =19+29+37\\ & =85\end{array}$$