Ans is option (b) 56
Explanation:
The sum of the five numbers = 5 × 213 =1065
The sum of the first two numbers = 2 × 233.5 = 467
The sum of the last two numbers = 542
Then the sum of the four numbers = 467 + 542 =1009
So, the third number will be = 1065 – 1009
= 56