The mass of Aravin to the mass of Bob is in the ratio 17 : 13. If the difference in their masses is 12 kg, find their combined mass.

2 answers

a/b = 17/13
a-b = 12 (why not b-a=12?)

(b+12)/b = 17/13
13(b+12) = 17b
13b + 156 = 17b
156 = 4b
b=39
a=51

a/b = 51/39 = 3*17/3*13 = 17/13
90