8. 4 tins of soup have a masss of 1.8 kg . 3 tins of soup and 2 packets of soup harve a mass of 1420 g . Find the mass of 7 tiins of soup and 5 packets of soup. Give sour answer in killograms.

To solve this, let's denote the mass of one tin of soup as \( t \) kg and the mass of one packet of soup as \( p \) kg. From the information given, we can set up the following equations: 1. From the first statement, we know that: \[ 4t = 1.8 \text{ kg} \quad \Rightarrow \quad t = \frac{1.8}{4} = 0.45 \text{ kg} \] 2. From the second statement, we convert 1420 g to kg: \[ 1420 \text{ g} = 1.42 \text{ kg} \] And we have: \[ 3t + 2p = 1.42 \] Substituting \( t = 0.45 \): \[ 3(0.45) + 2p = 1.42 \quad \Rightarrow \quad 1.35 + 2p = 1.42 \quad \Rightarrow \quad 2p = 1.42 - 1.35 = 0.07 \quad \Rightarrow \quad p = \frac{0.07}{2} = 0.035 \text{ kg} \] Now, substituting back to find the mass of 7 tins of soup and 5 packets of soup: \[ \text{Mass} = 7t + 5p = 7(0.45) + 5(0.035) = 3.15 + 0.175 = 3.325 \text{ kg} \] Thus, the mass of 7 tins of soup and 5 packets of soup is **3.325 kg**.