Answer:

152

Step-by-step explanation:

8:5 = 247

8x + 5x = 247

13x = 247

divide both by 13

x=19

substitue the x to the equation: 8x + 5x = 247

8(19) + 5(19) = 247

152 + 95 +247

the math books to science books is 8:5

and the number of math books is 152