Blog

Parin Sir > Quantitative Aptitude (Maths) > Profit And Loss > Examples 16 to 20 > Examples 16 to 20

Examples 16 to 20

June 14, 2020
Category: Examples 16 to 20

No Comments

(16) Successive discounts of 30% and 50% is equivalent to a single discount of how many per cent ?

Soln. Let M. P. = Rs. 100

$\therefore$ S.P. = $\frac{100-30}{100}\times\frac{100-50}{100}\times100$ = Rs. 35

$\therefore$ Discount = M. P. – S. P. = 100 – 35 = Rs. 65

$\therefore$ Discount ( % ) = 65 %

$\therefore$ Total discounts = $\left (x+y-\frac{xy}{100} \right )$ % = $\left (30+50-\frac{30\times50}{100} \right )$ % = 65 %

(17) If a commission of 10 % is given on the list price, the gain is 50 %. Find the gain per cent, if the commission is increased by 10 % ( or increased to 20 % ).

Soln.

Before

After

Let, List price = Rs. 100

& Commission = 10 %. = Rs. 10

S.P. = 100 – 10 = Rs. 90,

Now, Gain = 50 % $\large \Rightarrow$ S. P. = 150 %

i.e.

S. P.		C. P.
150		100
90		( ? )

C.P. = $\frac{90\times100}{150}$ = Rs. 60.

Now, for List price = Rs. 100

& Commission = 20 %. = Rs. 20

S.P. = 100 – 20 = Rs. 80,

Now, Gain = S. P. – C. P. = 80 – 60

= Rs. 20

i.e.

C. P.		Gain
60		20
100		( ? )

Gain = $\frac{100\times20}{60}$ = 33 $\frac{1}{3}$ %

(18) A trader allows a discount of 20 % for cash payment. How much % above the cost price must he mark his goods to make a profit of 10 % ?

Soln. Let, the cost price ( C.P. ) = 100 Rs.

$\frac{100+10}{100}\times$ C. P. = $\frac{100+20}{100}\times$ M. P.

$\frac{110}{100}\times 100 \times \frac{100}{80}= M.P.$

M.P. = Rs. 137.5 Required % = 37.5 %

(19) Pure ghee costs Rs. 200 per kg. After adulterating it with vegetable oil costing Rs. 60 per kg, a shopkeeper sells the mixture at the rate of Rs. 100 per kg, thereby making a profit of 25 %. In what ratio does he mix the two ?

Here,

S.P. = 125 %

Cost Price = 100 %.

S.P. C. P.

125 100

100 ( ? )

Now, by the rule of allegation,

C.P. = $\frac{100\times 100}{125}$ = Rs. 80.

$\therefore$ Ratio = 20 : 120 = 1 : 6

(20) Sonal purchased a purse at $\left (\frac{5}{7} \right )^{th}$ of its selling price and sold it at 10 % more than its S.P. Find her gain percent.