Question

Два кг сплаву меди и олова содержат 40% меди сколько кг олова нужно добавить до этого сплаву, чтоб одержать сплав который содержит 25% меди?

Answer 1

0,4*2=0,8кг меди в сплаве
пусть х кг олова нужно добавить
тогда 2+х это масса полученного сплава
масса меди в нём не изменилась
0,25(2+х)=0,8
0,5+0,25х=0,8
0,25х=0,3
х=1,2кг
ответ: 1,2кг олова

Answer 2

Calculating the Amount of Tin to Add to the Alloy

To calculate the amount of tin needed to add to the alloy to obtain a mixture containing 25% copper, we can use the following approach:

Let's assume the initial amount of copper-tin alloy is 2 kg, and it contains 40% copper. We need to find out how much tin needs to be added to achieve a mixture containing 25% copper.

First, we can calculate the amount of copper and tin in the initial alloy: - Copper in the initial alloy = 40% of 2 kg = 0.4 * 2 kg = 0.8 kg - Tin in the initial alloy = 2 kg - 0.8 kg = 1.2 kg

Now, we need to find the amount of tin needed to achieve a mixture containing 25% copper. Let's denote the amount of tin to be added as x kg.

The total weight of the new alloy will be 2 kg (initial alloy) + x kg (tin to be added).

The equation for the copper content in the new alloy can be expressed as: - Copper in the new alloy = 25% of (2 kg + x kg)

To solve for x, we can set up the following equation: - 0.25 * (2 + x) = 0.8 (the total amount of copper in the initial alloy)

Solving for x: - 0.25 * (2 + x) = 0.8 - 2 + x = 0.8 / 0.25 - 2 + x = 3.2 - x = 3.2 - 2 - x = 1.2

So, 1.2 kg of tin needs to be added to the alloy to obtain a mixture containing 25% copper.

This calculation is based on the given information and the principles of mixture problems.