A barrel of oil weighs 120 kg. After half of the oil is poured out, the barrel weighs 62 kg. How many kg?

A barrel of oil weighs 120 kg. After half of the oil is poured out, the barrel weighs 62 kg. How many kg?

Weight of oil: (120-62) × 2 = 116 (kg)
Barrel weight: 120 - 116 = 4 (kg)

For a barrel of oil, the connected weight is 120kg. After 20% is used, the connected weight is 96.6kg. How much is the weight of an empty barrel?

(120-96.6) / 20% = 117 kg
120-117 = 3kg
The empty barrel weighs 3kg

Divide a cube with an edge length of 20 cm into two identical cuboids. The surface area of each cuboid is______ ．

The length of each cuboid: 20 △ 2 = 10 cm, the width and height are 20 cm, 10 × 20 × 4 + 20 × 20 × 2 = 800 + 800 = 1600 (square cm). Answer: the surface area of each cuboid is 1600 square cm. So the answer is: 1600 square cm