Answer:
Step-by-step explanation:
From the law of variation,
y <> 1/x, where <> is the constant of proportionality. Therefore
y = k/x where k is a constant
3 = k/5 and k = 15
To find x when y = 2.5(5/2)
Go back to the second equation
y = k/x
5/2 = 15/x
When you cross multiply
5x = 30.
Divide through by 5,
x = 6.
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
You have to change the denominator of 6/10 into 100 then you will get 60/100 then you add 15/10+60/100
