Harga satu gelas kacang ijo yaitu 2 kali lipat dari harga 1 mangkuk. Jika harga 6 gelas dan 14 mangkuk adalah 39 ribu maka harga untuk 12 mangkuk adalah?

<p>Misalkan x = kacang hijau dan y = mangkok maka persamaan matematikanya :</p><p>x = 2y &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ....(1)</p><p>6x + 14y = 39.000 &nbsp; ...(2)</p><p>Substitusikan persamaan (10 ke persamaan (2)</p><p>6x + 14y = 39.000</p><p>6(2y) + 14y = 39.000</p><p>12y + 14y = 39.000</p><p>26y = 39.000</p><p>y = 39.000 : &nbsp;26</p><p>y = 1.500</p><p>&nbsp;</p><p>Substitusikan y = 1500 ke persamaan (1)</p><p>x = 2y &nbsp; &nbsp;</p><p>x = 2(1500)</p><p>x = 3.000</p><p>&nbsp;</p><p>Harga 12 mangkok = 12y</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 12(1500)</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 18.000</p><p>Jadi harga 12 mangkok adalah Rp. 18.000; &nbsp; &nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p>