5 years ago, the average age of A, B, C and D was 50 years. With E joining them now, the average age of all the five is 54 years. How old is E ?

50

5 years ago, the average age of A, B, C and D = 50 years.

Sum of A, B, C and D = 50 × 4 = 200 years

Sum of the present age of A, B, C and D = 50 × 4 + 4 × 5 = 2000 + 20 = 220 years

With E joining them now, the average age of A, B, C , D and E = 54 years.

Sum of the present age of A, B, C, D and E = 54 × 5 = 270 years

∴ Present age of E =( Sum of the present age of A, B, C, D and E) - (Sum of the present age of A, B, C and D)

∴ Present age of E = (270 – 220) years = 50 years