CBSE Class 10 Answered

assume that he invested Rs. x and Y respectively at 12 % and 10%

So,

12x/100+10y/100=130

and

12y/100+10x/100=134

so,

 12x+10y=13000

and

10x+12y=13400

So,

6x+5y=6500

5x+6y=6700

note that the coefiicients are interchanfing places, so we can use the method of once adding the equations and one subtracting them to get new, simpler equations and solving them.

or else you can use any of the standard methods of solving the system.

Now we have

11x+11y=13200 i.e. x+y=1200

x-y=-200

Solving these new equations we get

2x=1000

x=500

so y=700