# teacher please solve and give only two some that is 7th and 12th

Given that monthly pocket money of ravi and sanjeev are 5:7

so let

Monthly pocket money of ravi and sanjeev be=5x and 7x

And given expenditure are in ratio 3:5 So,

Expenditures=3y and 5y

Given that they save Rs 80

$5x-3y=80\cdots \left(1\right)\phantom{\rule{0ex}{0ex}}7x-5y=80\cdots \left(2\right)$

Multiplying eqn 1 with 5 and eqn 2 with 3 we get

$25x-15y=400\phantom{\rule{0ex}{0ex}}21x-15y=240\phantom{\rule{0ex}{0ex}}-+-\phantom{\rule{0ex}{0ex}}\cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots \phantom{\rule{0ex}{0ex}}4x=160\phantom{\rule{0ex}{0ex}}\cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots \cdots $

x=40

and y=40 So we get monthly pocket money of Ravi=Rs 200

And pocket money of sanjeev is Rs 280.

Ask remaining queries in seperate thread.

Regards.

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