Given ratio of the numbers = 6:13
Let the numbers be 6x and 13x
LCM of these two numbers is given as 312
And 6x and 13x are co-prime nos.
∴L.C.M.(6x,13x)=(6×13)×x=78x
L.C.M of the numbers =312
78x=312
X=4
The numbers are 6x=6(4)=24
And 13x=13(4)=52
therefore sum of numbers is 52+24=76