The mass of 1 liter of oil is 0.85 kg. Find the mass of 7.4 liters of oil.

To solve this problem, we will use the proportioning. Let us denote the desired mass by x.
Let’s make the following proportion:
1 liter = 0.85 kg;
7.4 liters = x kg;
Let’s solve this proportion using the method of diagonals, multiplying each diagonal with each other.
1 * x = 7.4 * 0.85;
Let’s sort this equation by performing the possible multiplication actions:
1 * x = 6.29;
Find x by freeing the unknown variable x from the coefficient.
x = 6.29 kg.
This means that the mass of 7.4 liters of oil is 6.29 kg.
Answer: 6.29 kg of oil.