We will let;
X = the number of kilos of rice with the amount of P26 per kilo.
150 - X = the number of kilos of rice with the amount of P24 per kilo.
26X + 24(150-X) = (25)(150)
26X + 3,600 - 24X = 3,750
26X - P24X = 3,750 - 3,600
2X = 150
2X / 2 = 150 / 2
X = 75
Therefore, the number of kilos of rice mixed for P26 per kilo is 75 kilos. And the number of kilos of rice for P24 per kilo is also 75 kilos.