Question

2Decrease R420 in the ratio 4:7​

Answer 1

Step-by-step explanation:

Let the numbers are 4x and 7x. According to the question if each number is increased by 20, the ratio becomes 7 : 9.

Then,

( 4x + 20 ) : ( 7x + 20 ) = 7 : 9

9( 4x + 20 ) = 7( 7x + 20 )

9( 4x ) + 9( 20 ) = 7( 7x ) + 7( 20 )

9( 20 ) - 7( 20 ) = 7( 7x ) - 9( 4x )

2( 20 ) = 49x - 36x

40 = 13 x

40 / 13 = x

Therefore, number are :–

4 x = 4( 40 / 13 ) = 160 / 13

7 x = 7( 40 / 13 ) = 280 / 13