Question

A packet of salt increases by 9cents the old price is 4/5 of the new price calculate the old and new price

Answer 1

Question:

A packet of salt increases by 9cents the old price is 4/5 of the new price calculate the old and new price.

Solution:

Let the old price of the packet be x

New price of the packet = $x\:\: \± 9$

$\frac{4}{5}\textsf{ of x + 9 }$

$\frac{4}{5}\times x +9 = 4x+\frac{36}{5}$

$\frac{4}{5}\times x = 4x+\frac{36}{5}-9$

$\frac{4}{5}\times x = 4x+\frac{36}{5}-\frac{9}{1}\times\frac{5}{5}$

$\frac{4}{5}\times x = 4x+\frac{36}{5}-\frac{45}{5}$

$\frac{4}{5}\times x = 4x-\frac{9}{5}$

$4x = 4x-\frac{9}{5}\times 5$

$4x=4x-9$

$4x+9=4x$

$9=\frac{4x}{4x}$

$x=9$

Old Price of the Salt Packet = $9\times4$ $= 36$

New Price of the Salt Packet $=9\times4+9$ $= 36+9$ $= 45$

Answer:

Old Price of the Salt Packet = $9\times4$ $= 36$

New Price of the Salt Packet $=9\times4+9$ $= 36+9$ $= 45$

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