First of all, it is necessary to find out whether a big boat can afford it or a small boat can afford it. So we need to find their common multiple to compare. The common multiple of 4 and 3 is 12. 4×3= 12 3× 10=30 yuan 3×4= 12 4×8=32.30 = less than 32, so it is inferred that it is mainly to rent large ships. 142÷4=35+2. So we have 35 big ships, 1 small boat. 35× 10+8=358