Question

The average of 4 numbers is 30 . if the sum of first 3number-is 85 the fourth number is ​

Answer 1

Answer:

Sum of 4 numbers = 4 × 30 = 120

0Sum of first 3 numbers = 3 × 85 = 255

Sum of last 3 numbers is not given. So, let it be 0.

$\red{{ \bold{ \sf{ \therefore{Fourth \: number = (225 + 0) - 120}}}}}$

$\red{ \bold{ \sf{ \therefore{Fourth \: number \: = 255 - 120}}}}$

$\red{ \bold{ \sf{ \therefore{Fourth \: number \: = 135}}}}$