Question

Two numbers are in ratio 3:4 if each is increased by 10 the ratio between the new number so formed is 5:7 findvthe original no.

Answer 1

Given,
x:y=3:4
x+10:y+10=5:7
Now,
x/y=3/4
4x=3y
4x-3y=0 .......(i)
Again,
(x+10)/(y+10)=5/7
7(x+10)=5(y+10)
7x+70=5y+50
7x-5y=-20. .......(ii)
Now,
Multiplying eq (i) with 5 and eq (ii) with and then subtracting eq (i) from (ii):-
21x-15y-(20x-15y)=-60-0
x=-60
Now,
So,
3x/4=y
3*-60/4=y
3*-15=y
y=-45

Hope this helps you!