Examples: Profit and Loss as Percentage Video Lecture - Class 7

hello friends this video on comparing
quantities part 15 is brought to you by
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let us now quickly have a look at some
of the questions question number one
cost of an item is rupees fifty it was
sold with a profit of twelve percent
finding the selling price so the cost
price is given as rupees fifty so the
cost price here is rupees fifty and the
profit percentage is given as 12 percent
so profit percentage is twelve percent
and we have to find out the selling
price so how would we find out the
selling price so for that we we need to
find out the actual profit because this
is the profit percentage but what is the
actual profit that is what we need to
find out first so we already saw that
profit percentage is what it is nothing
but profit which is made out of the cost
price multiplied by hundred so this is
your profit percentage so we can write
it as twelve is equal to profit divided
by CP which is nothing but 50 into
hundred so 50 into 2 or we can say
profit is equal to 12 divided by 2 so 2
six to twelve so the profit is rupees
six so now that you know the profit you
know the cost price you can very easily
find out selling price so selling price
would be equal to cost price plus profit
so therefore it would be rupees 15 plus
6 so the selling price of the item would
be rupees fifty six question number two
a shopkeeper bought a chair for rupees
375 but the shopkeeper bought it for
this much amount that means this is the
cost price so the cost price is rupees
375 and sold it for rupees four hundred
the selling price is rupees 400 find the
gain percentage so gain is nothing but
profit so how much gain will the
shopkeeper make out of it that is
nothing but SP minus CP that is selling
price minus cost friends which would be
400 minus 375 that is equal to rupees 25
so this would be his game now you have
to calculate gain percentage so to
calculate gain percentage you'll have to
write gain divided by cost price in 200
percent so this can be written as 25
divided by 375 in 200 percent so this
would be 5 5 so 25 5 into 75 is 375 then
515 is a 75 so 100 divided by 15 percent
which is nothing but six point six six
percent so this would be the gain person
question of the three and items were
sold for rupees five forty at a loss of
five percent so the item was sold for
the piece 540 that means selling price
is rupees five forty and what is the
loss percentage loss percentage is five
percent so we have to calculate the cost
friends so how could we calculate the
cost price so for that we need to
calculate the actual loss right how do
we calculate the actual loss so actual
loss would be the loss percentage on the
CP right so five percent of CP let us
assume that the CP is X the cost price
is X so loss would be five percent of X
that is 5 by 100 into X this would be
the actual loss now we already know that
loss is given by CP minus SP that is the
difference of the cost price and the
selling price so cost prices
selling price is 540 and what is lost
losses 5x by hundred that is what we
calculated here right loss is 5x by
hundred so now we have to solve this
equation so this becomes 5x is equal to
100 into X minus 540 so that is how we
solve an equation I'd cross multiply so
this can be written as 5x is equal to
hundred X minus 54,000 or we can say
that 5x minus 100x is equal to minus
54,000 so after this let me do it here
so 5x minus 100x would be minus 95 X is
equal to minus 54,000 or X would be
equal to minus 54,000 divided by minus
95 so a negative integer divided by a
negative integer gives a positive
integer and when you actually divide
this you get this value as would be 568
that for the cost price of the item
would be 2 these five sixty-eight point
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