Ahmad had two planks of the same length. He sawed one plank into equal parts of length 100 cm. In each part he drilled 6 small holes as shown in Figure 1. After that, he sawed the other plank into equal parts of length 2.5 m and in each part, he drilled 8 big holes as shown in Figure 2. When he finished drilling, he counted that there were 42 more small holes than big holes. If all the holes are spaced equally, how many holes were there altogether?
