model 4 sold & brought Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (c)

C.P. of 5 pencils = Rs.1.

S.P. of 5 pencils = Rs.$5/3$

Gain = $5/3 - 1 = 2/3$

Gain % = ${2/3}/1 × 100 = 66{2}/3%$

Using Rule 13,

Here, a = 5, x = 1, b = 3, y = 1

Gain% = $({ay - bx}/{bx} × 100%)$

= ${5 - 3}/3 × 100% = 200/3 = 66{2}/3%$

Answer: (d)

C.P. of 100 oranges = Rs.350

S.P. of 12 oranges = Rs.48

S.P. of 100 oranges

= $48/12 × 100$ = Rs.400

Profit = Rs. (400 - 350) = Rs.50

Profit % = $50/350 × 100 = 100/7 = 14{2}/7%$

Using Rule 13,

Here, a = 100, x = 350, b = 100, y = $48/12$ × 100 = 400

Gain% = $({ay - bx}/{bx})$ × 100%

= ${100 × 400 - 100 × 350}/{100 × 350}$ × 100%

= ${40 - 35}/35 × 100%$

= $100/7% = 14{2}/7$%

Answer: (b)

Suppose the number of oranges bought

= LCM of 10 and 9 = 90

C.P. of 90 oranges = $25/10 × 90$ = Rs.225

S.P. of 90 oranges = $25/9 × 90$ = Rs.250

Profit % = $25/225 × 100 = 100/9 = 11{1}/9%$

Using Rule 13,

Here, a = 10, x = 25, b = 9, y = 25

Gain% = $({ay - bx}/{bx})$ × 100%

= $({10 × 25 - 9 × 25}/{9 × 25}) × 100%$

= $({250 - 225}/{9 × 25}) × 100% = 100/9 = 11{1}/9%$

Answer: (c)

Let the cost price of 1 book be x

Cost price of 3 books = 3x

and, cost price of 12 books = 12x

Selling price of 12 books = 1800

= 12x + 3x = 15x

15x = 1800; x = $1800/15 = 120$

The cost price of each book = Rs.120

Answer: (a)

C.P. = 12; S.P. = 12 × 1.25 = 15

Total Profit = 15 - 12 = 3

% gain = $3/12 × 100$ = 25%

Answer: (d)

Cost price of 1 orange = Rs.$3/7$

Cost price of 100 oranges

= $3/7 × 100 = 300/7$

100% = $300/7$

133% = $300/7 × 133/100$ = Rs.57