Out of 6 numbers, the average of first 5 is 19 and last 5 is 20. If the last number is 21. Find the first number?
Sum of first five numbers = 19 × 5 = 95 Given that last number = 21 Sum of all the six numbers = 95 + 21 = 116 .....(i) Sum of last 5 digits = 20 × 5 = 100 …...(ii) By subtracting (ii) from (i), we will get the first number, the first number, First number = (i) – (ii) = 116 – 100 = 16
