if each number is multiplied by x and decreased by 25, then the mean of the numbers also gets multiplied by x and decreased by 25. Let the original mean be A.

Then

AX-25=A

Given A=75

Substitute

75X-25=75

X=4/3

Hello Zareen

x comes out to be 4/3.

x1 +x2 +x3 + ......+ x30 = 75*30

X( x1 + x2 + x3 +.......+ x30) - 25*30 = 75*30

X(75*30) -25*30 = 75*30

X(75*30)= 30* ( 75+25)

X = 4/3.

Good luck.

Hello Zareen

x comes out to be 4/3.

x1 +x2 +x3 + ......+ x30 = 75*30

X( x1 + x2 + x3 +.......+ x30) - 25*30 = 75*30

X(75*30) -25*30 = 75*30

X(75*30)= 30* ( 75+25)

X = 4/3.

Good luck.