Question

what number should be added to each of the numbers 12 22 to 42 and 72 so that the resulting number may be in proportion

Answer 1

let x should be added.

so,first number= 12 +x.

second number =22 + x.

third number = 42 + x.

forth number = 72 + x.

so to be proportional of these numbers would be in this way.

( 12 + x ): ( 22 + x ) :: ( 42 + x ) : ( 72 + x )

now,product of extremes = product of mean.

( 12 + x ) (72 + x ) = ( 42 + x ) ( 22 + x )

12×72 + 12x + 72x + x ^2 = 42×22 + 42x + 22x + x ^2

=864 + 84x + x ^2 =924 + 64x + x ^2
=84x - 64x + x ^2- x ^2 = 924−864

= 20 x =60
x = 60/20

x = 3.

Answer 2

hope its help u. mark as correct ans plz