Question

i need the answer for this question.

Answer 1

Given,Mean=78
i.e.,Total of 'fx' / Total of 'f'=78
=>1930+340x+190y/50=78
=>340x+190y=1970
=>34x+19y=197 --- (1)
Also,
8+6+12+4x-1+2y+3=50
=>2x+y=11 --- (2)

34x+19y=197 --- ×1
=>34x+19y=197 ---(3)
2x+y=11 --- ×17
=>34x+17y=187 ---(4)

substracting equation (3)-(4)

(34x+19y)-(34x+17y)=197-187
=>2y=10
=>y=5

putting y=5 in equation (2)

2x+y=11
=>2x=11-5
=>2x=6
=>x=3

{x=3,y=5}