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

Answer: (b)

Let the CP of each ball = x.

Then, clearly the cost price of (17 - 5) balls = Rs.720

i.e., 12x = 720 ⇒ x = 60 i.e. Rs.60

Answer: (a)

Using Rule 1,

CP of 120 excercise books = Rs.(120 × 3) = Rs.360

SP of 40 at Rs.4 each = Rs.(40 × 4) = Rs.160

SP of 60 at Rs.5 each = Rs.(60 × 5) = Rs.300

SP of remaining 20 books = Rs.(20 × 3) = Rs.60

Total SP = Rs.(160 + 300 + 60) = Rs.520

Profit % = Rs.(520 - 360) = Rs.160

Profit% = $160/360 × 100 = 400/9 = 44{4}/9%$

Answer: (a)

Let the person buy 10 articles.

Total CP = Rs.$(1 + 5/4)$ = Rs.$9/4$

SP of 10 articles = Rs.$2/9 × 10$ = Rs.$20/9$

Loss = Rs.$(9/4 - 20/9)$ = Rs.$({81 - 80}/36)$ = Rs.$1/36$

Now, if loss is Rs.$1/36$, number of articles = 10

If loss is Rs.3, number of articles = 36 × 10 × 3 = 1080

Answer: (d)

Let number of articles bought = 6 × 5 = 30

C.P. of 30 articles = Rs.$(5/6 × 30)$ = Rs.25

S.P. of 30 articles = Rs.$(6/5 × 30)$ = Rs.36

Gain % = ${36 - 25}/25 × 100$ = 44%

Using Rule 13,

Here, a = 6, x = 5, b = 5, y = 6

Gain% = $({ay - bx}/{bx})$ × 100%

= $({6 × 6 - 5 × 5}/{5 × 5})$ × 100%

= $({36 - 25}/25) × 100% = 11/25 ×100%$ = 44%

Answer: (d)

Total C.P. = Rs.32

Total S.P. = Rs.(18+2) = Rs.20

Loss = Rs.(32-20) = Rs.12

Loss per cent = $12/32 × 100$ = 37.5%

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%

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

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