A father's age is now three times that of his elder daughter. Five years back his age was eight times that of his younger daughter .If the difference of ages of the two daughters is 5 years ,what is the age of the father now?

Let the father's age be F, elder daughter be E, and younger daughter be Y. From the problem: F = 3E, F-5 = 8(Y-5), and E-Y = 5. Substituting E = Y+5 into F = 3E gives F = 3(Y+5) = 3Y+15. Also from the second equation: F-5 = 8Y-40, so F = 8Y-35. Equating both expressions: 3Y+15 = 8Y-35, giving 5Y = 50, so Y = 10. Then E = 15 and F = 45. The father is currently 45 years old.