In University `PQR, the total number of students is 28% of the total number of students in University `XYZ. If in University ‘PQR’ 60% of the total students study either in science stream or in commerce stream and the respective ratio between the number of students studying in science stream and the number of students studying in commerce stream is 7 : 5, what is the number of students studying in science stream?

Let the total number of students in all colleges together = $$100x$$

=> Number of students in A = $$\frac{25}{100} \times 100x = 25x$$

Number of students in C = $$\frac{60}{100} \times 25x = 15x$$

Number of students in college D = $$\frac{3}{4} \times 15x = \frac{45x}{4}$$

Number of students in E = $$\frac{1}{2} \times 15x = 7.5x = 450$$

=> $$x = \frac{450}{7.5} = 60$$

Number of students in university PQR = $$\frac{28}{100} \times 6000 = 1680$$

Students studying in science or commerce stream in university PQR = $$\frac{60}{100} \times 1680 = 1008$$

Ratio between students of science and commerce stream = 7 : 5

=> Number of students studying in Science stream = $$\frac{7}{12} \times 1008 = 588$$