A kind of wood is 3.5 meters long, and its cross section is a square with side length of 20 cm. How many cubic meters is the volume of 50 pieces of wood?

A kind of wood is 3.5 meters long, and its cross section is a square with side length of 20 cm. How many cubic meters is the volume of 50 pieces of wood?

20cm = 0.2m
The volume is 0.2x0.2x3.5x50 = 7 cubic meters

It is known that each cubic meter of wood weighs 400 kg, and the volume of each ton of coal is 5 / 7 cubic meters
M, how many tons of wood and coal can this ship load at a time to make full use of its load and capacity?

Wood: (890 * 7 / 5-560) / (7 / 5-0.4) = 686 cubic meters, 686 * 0.4 = 274.4 tons
Coal: 890-686 = 204 cubic meters, 204 * 7 / 5 = 285.6 tons

The volume of a cuboid wood is 0.078 cubic meters. It is known that the wood is 1.3 meters long and 3 decimeters wide. How many decimeters should it be high? Sun Jian mistakenly calculated the height as 3 decimeters. In this way, how much more is the volume of this wood than 0.078 cubic meters?

① 0.078 ÷ (1.3 × 0.3) = 0.2 (m); ② 1.3 × 0.3 × (0.3-0.2), = 0.39 × 0.1, = 0.039 (M3); answer: the height is 2 decimeters, the volume of this wood is 0.039 m3 more than 0.078 m3