Question

The average of A, B and C is 18 and that of C, D and E is 12 and that of E and F is 6.5 and that of E and C is 3.5. What is the average of A, B, C, D, E and F?
1. 24
2. 16
3. 18
4. 22

Answer 1

Correct Answer - Option 2 : 16

Given 

The average of A, B and C = 18 years 

The average of C, D and E = 12 years 

Formula Used 

Average = (sum of observation)/(No. of observation)

Calculation 

⇒ Total age of A, B and C = 18 × 3 = 54  -----(i)

⇒ Total age of C, D and E = 12 × 3 = 36  ------(ii)

⇒ E + F = 13 ---(iii)

⇒ E + C = 7 ----(iv)

⇒ from iii and iv 

⇒ F - C = 6 -----(v) 

⇒Adding (i), (ii) and (v) 

⇒ A + B + C + C + D + E + F - C = 54 + 36 + 6 

⇒ A + B + C + D + E + F = 96 

⇒ the average = 96/6 = 16 

∴ the average of A, B, C, D, E and F is 16 years