I invest $x at 3%/annum & $y at 4%/ annum.Annual income fm this is $22. If I invested $y at 3% & $x at 4%, my income would be $20/annum. find x.
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The idea is to use both equations to solve for one variable and substitute it back for the other. So:
1) .03x + .04y = 22 and
2) .04x + .03y = 20 so combining (adding) equations gives you
3) .07x + .07y = 42 divide each term by .07 to reduce equation
4) x + y = 600 and set value for y
5) y = 600 - x
If you substitute 600 - x for y in equation 1, you should find that x = $200 and y = $400.
Let's do simultaneous equations:
Multiply both eqn by 10 to get whole number
Multiply eqn 3 by 4 and eqn 4 by 3
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