Answer: Option B. -> Rs.17,100
Answer: (b)Let 'x' be the marked price Single Discount = 15%100 - 15 = 8585% of x = 17,000$x = {17,000}/85 × 100$ = Rs.20,000Required SP= $20,000 × 95/100 × 90/100$= 180 × 95 = Rs.17100 Using Rule 2,If article is sold on D% discount, thenSP = ${\text"MP"(100 - D)}/100$MP = ${\text"SP" × 100}/{100 - D}$

Answer: Option D. -> 49.6%
Answer: (d)Using Rule 5,Single equivalent discount for successive discounts of 10% and 20%.= $(10 + 20 - {20 × 100}/100)$% = 28%Single equivalent discount for 28% and 30%.= $(28 + 30 - {28 × 30}/100)$% = 49.6%

Answer: Option C. -> Rs.205.20
Answer: (c)A single discount equal to the two successive discounts= $(10 + 5 - {10 × 5}/100)%$ = 14.5%Selling price of the article= 85.5% of Rs.240= Rs.${85.5 × 240}/100$ = Rs.205.20Using Rule 3,Here, M.P. = Rs. 240, $D_1 = 10%, D_2$ = 5%S.P. = M.P.$({100 - D_1}/100)({100 - D_2}/100)$= $240({100 - 10}/100)({100 - 5}/100)$= $240 × 90/100 × 95/100$= Rs.205.20

Answer: Option B. -> 15%
Answer: (b)Marked price = Rs.160After 10% discountS.P = $90/100 × 160$ = Rs.144Let other discount = x%${(100 - x)}/100 × 144$ = Rs.122.40100 - x = $12240/144$100 - x = 85x = 100 - 85 = 15%Using Rule 3,S.P. = M.P.$({100 - D_1}/100)({100 - D_2}/100)$122.40 = 160$({100 - 10}/100)({100 - D_2}/100)$${1224000}/160 = 90 × ({100 - D_2}/1)$$1224000/{160 × 90} = 100 - D_2$$85 = 100 - D_2 ⇒ D_2$ = 15%

Answer: Option D. -> increased by 5.3%
Answer: (d)Using Rule 5,Let the original price be Rs.100Increased price = Rs.130Equivalent discount= $(10 + 10 - {10 × 10}/100)$ = 19%Ultimate price of the article = 81% of 130 = 105.3i.e. increase by 5.3%.

Answer: Option B. -> Rs.1440
Answer: (b)Equivalent discount for successive discounts of 20% and 10%= $[20 + 10 - {20 × 10}/100]%$ = 28%Net selling price = 72% of 2000= Rs.${72 × 2000}/100$ = Rs.1440Using Rule 3,Here, M.P. = Rs.2000, $D_1 = 20%, D_2$ = 10%S.P. = M.P.$[({100 - D_1}/100)({100 - D_2}/100)]$= M.P.$[2000 × ({100 - 20}/100) × ({100 - 10}/100)]$= $2000 × {80 × 90}/10000$ = Rs.1440

Answer: Option B. -> 28%
Answer: (b)Using Rule 5,Successive discounts of x% and y%= $(x + y - {x + y}/100)%$Required discount= $(20 + 10 - {20 × 10}/100)$%= 30 - 2 = 28%

Answer: Option D. -> 10%
Answer: (d)Price after 10% first discount= $1000 × {100 - 10}/100$=$1000 × 90/100$ = Rs.900Given :Price after second discount = Rs.810Second discount= 900 - 810 = Rs.90Percentage of second discount= ${90 × 100}/900$ = 10%

Answer: Option B. -> 15%
Answer: (b)Let the second discount be x%.Then, 90 % of (100 - x) % of 800 = 612$90/100 × {100 - x}/100 × 800 = 612$100 - x = ${612 × 100}/{90 × 8}$ = 85x = 100 - 85 = 15%Using Rule 3,Here, M.P. = Rs.800, S.P. = Rs.612, $D_1 = 10%, D_2$ = ?S.P. = M.P.$({100 - D_1}/100)({100 - D_2}/100)$612 = 800 × $({100 - 10}/100) × ({100 - D_2}/100)$612 = $800 × 90/100 × {100 - D_2}/100$$6120/72 = 100 - D_2$$D_2 = {100 - 6120}/72$= ${7200 - 6120}/72$ = 15%

Answer: Option B. -> 46%
Answer: (b)Single of discount for successive discounts 10% and 20%= $(20 + 10 - {20 × 10}/100)$% = 28%Equivalent discount for discounts 28% and 25%= $(28 + 25 - {28 × 25}/100)$%= 53 - 7 = 46% Using Rule 4,If $D_1, D_2, D_3$ are successive discounts, then equivalent discount/overall discount is (in percentage)100 - $[({100 - D_1}/100)({100 - D_2}/100)({100 - D_3}/100) × 100]$