Question

$\large\red{\frak{Question}}$
When water freezes it's volume decreases by 4%.What volume of water is required to make 221cm³ of ice.
A-212cm³
B-211cm³
C-213cm³
D-210cm³​

Answer 1

Let volume of water be x.

Ice cube required= 221

Volume after freezing= x X 104% = 221

= x X 104/ 100 = 221

= x = (221 X 100) / 104

= x= 212.5

So, 212.5 cm³ volume if water is required to make 221 cm³ of ice.

hope this helps you dear

Answer 2

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Step-by-step explanation:

We are given that the volume of water increases by 4 % when we freeze it and we need to find the volume of water required to make 221 cm³ of ice.Now let us assume an unknown variable for the volume of water required to make ice which has a volume of 221 cm³ . Let the volume of water required by x cm³. Since in ice form, the volume is 4 % more than the volume in liquid state, we can write the following expression for volume, taking into consideration the volume of ice that we need to obtain.

x+4 % of x=221 cm³

This expression is obtained based on the fact that there is an increase of 4 % in the volume of water as we lower its temperature to freeze it to obtain ice which has a volume of 221 cm³ .Now we can solve this equation in the following way.

$\[ \begin{array}{c} \displaystyle \rm x+\frac{4 x}{100}=221 \\ \\ \displaystyle \rm\frac{100 x+4 x}{100}=221 \\ \\ \displaystyle \rm\quad \frac{104 x}{100}=221 \\ \\ \displaystyle \rm\Rightarrow x=221 \times \frac{100}{104} \\ \\ \boxed{\color{olive} \displaystyle \rm\therefore x=212.5 cm ^{3} }\end{array} \]$

Hence, we need 212.5 cm³ of water if we want to obtain 221 cm³ of ice upon freezing. This is the required answer.