Q. Out of four number, the average of first three is 15 and that of the last three is 16, if the last number is 19, the first is ?
✅ Correct Answer: (B)
16
Explanation: Sum of four number = ( 15 x 3 + 19 ) = 64
Sum of last three number = ( 16 x 3 ) = 48
∴ first number = ( 64 – 48 ) = 16
Explanation by: Ruchi Sharma
Sum of four number = ( 15 x 3 + 19 ) = 64
Sum of last three number = ( 16 x 3 ) = 48
∴ first number = ( 64 – 48 ) = 16
Sum of last three number = ( 16 x 3 ) = 48
∴ first number = ( 64 – 48 ) = 16