Question

An alloy contains only zinc and copper and they are in the ratio of 7 : 9. If the weight of the
alloy is 8 kg, then find the weight of copper in the alloy.​

Answer 1

Given:

• An alloy contains only zinc and copper and they are in the ratio of 7 : 9

• the weight of the alloy is 8 kg,

To Find:

• find the weight of copper in the alloy.

$\large{\underline{\underline{ \sf \maltese{\:analysis:-}}}}$

➻ Now, the ratios of zind and copper are 7:9 and the sum of their weights is 8kg. so, let's consider the weight of zinc in the alloy as 7x and the weight of copper as 9x

__________________________________________

Solution:

now, the sum of 7x and 9x equals 8kg

$: \implies \sf \: 7x + 9x = 8kg \\ \\ \\ : \implies \sf 16x = 8 \: \: \: \: \: \: \: \\ \\ \\ : \implies \sf x = \frac{8}{16} \: \: \: \: \: \\ \\ \\ : \implies \sf x = \frac{1}{2} ^{ \bigstar}$

$\rm \therefore {\underline {\blue{ \: the \: value \: of \: x \: equals \: \frac{1}{2} kg}}}$

Now, as copper equals 9x let's find its weight

$: \implies \sf copper \: in \: the \: alloy= 9x \: \: \: \: \: \: \: \\ \\ \\ : \implies \sf \: copper \: in \: the \: alloy = 9 \times \frac{1}{2} \\ \\ \\ : \implies \sf copper \: in \: the \: alloy = 4.5kg$

$\blue{ \underline{ \boxed{ \pink{ \mathfrak{ \therefore \:copper \: in \: the \: alloy = 4.5kg ^{ \bigstar} }}}}}$