Two numbers are in the ratio 2:3. If 4 be subtracted from each , they are in the
ratio 3:5. Find the numbers.ans for class 7
Answers
Two numbers are in the ratio 2:3,if 4 be subtracted their ratio will be 3:5,find the numbers
Definition:
A relationship between two quantities, normally expressed as the quotient of one divided by the other.
Step-by-step explanation:
Let x and y be the numbers, therefore
[tex]\frac{x}{y} =\frac{2}{3} \\ 3x=2y\\ 3x-2y=0\\ [/tex] (1)
As the ratio after subtraction by 4 is given by,
[tex]\frac{x-4}{y-4} =\frac{3}{5} \\ 5(x-4)=3(y-4)\\ 5x-20=3y-12\\ 5x-3y=-12+20\\ 5x-3y=8[/tex] (2)
Multiply equation (1) by 5,
Multiply equation (2) by 3,
Subtract these equation,
[tex]15x-10y=0\\ 15x-9y=24[/tex]
(-) (+) (-)
__________
[tex]-y=-24\\ y=24\\[/tex]
Substitute the value of y in equation (1)
[tex]3x-2y=0\\ 3x-2[24] =0\\\\ 3x-48=0\\ x=\frac{48}{3} \\ x=16[/tex]
Therefore,the numbers are 16 and 24.