Question

(10) A mobile phone is sold for 8400 at a gain of 20%. The cost price of the mobile phone​

Answer 1

$\huge\mathtt{★\:Solution\: :-}$

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❖⠀$\tt{Let \:cost \:price\: of\: mobile \:be \:₹ \:x. }$$\tt{Given \:that \:selling\: price\: is\: ₹}$$\tt{ 8400 \:and \:gain \:is\: 20\%.}$

❖⠀$\tt{As \:per \:formula, \:SP\: =}$ $\tt\frac{(100\:+\:gain\%)}{100}$$\tt{༝\: CP}$

❖⠀$\tt{∴ \:By \:substituting\: we \:get,}$

↦$\tt{8400 \:=}$$\tt\frac{(100\:+\:20)}{100}$$\tt{༝ \:x}$

↦$\tt{8400 \:= }$$\tt\frac{120}{100}x$

↦$\tt{x \:=}$ $\tt\frac{8400\:༝\:100}{120}$

↦$\tt{₹\:7000.}$

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$\mathtt\blue{Answer\:⇝}$$\mathtt\pink{₹\:7000}$

Answer 2

$\huge{\underline{\underline{\boxed{\sf{\purple{Answer࿐}}}}}}$

Solution:−

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❖⠀\tt{Let \:cost \:price\: of\: mobile \:be \:₹ \:x. }Letcostpriceofmobilebe₹x. \tt{Given \:that \:selling\: price\: is\: ₹}Giventhatsellingpriceis₹ \tt{ 8400 \:and \:gain \:is\: 20\%.}8400andgainis20%.

❖⠀\tt{As \:per \:formula, \:SP\: =}Asperformula,SP= \tt\frac{(100\:+\:gain\%)}{100}100(100+gain%) \tt{༝\: CP}༝CP

❖⠀\tt{∴ \:By \:substituting\: we \:get,}∴Bysubstitutingweget,

↦\tt{8400 \:=}8400= \tt\frac{(100\:+\:20)}{100}100(100+20) \tt{༝ \:x}༝x

↦\tt{8400 \:= }8400= \tt\frac{120}{100}x100120x

↦\tt{x \:=}x= \tt\frac{8400\:༝\:100}{120}1208400༝100

↦\tt{₹\:7000.}₹7000.

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\mathtt\blue{Answer\:⇝}Answer⇝ \mathtt\pink{₹\:7000}₹7000