Discount
 The single discount equivalent to the discount series of 20%,10% and 5% is :

 11.66%
 31.6%
 35.66%
 32%

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Single equivalent discount for 20% and 10%
= 20 + 10 − 20 × 10 % = 28% 100
Single equivalent discount for 28% and 5%= 28 + 5 − 28 × 5 % = 31.6% 100
Correct Option: B
Single equivalent discount for 20% and 10%
= 20 + 10 − 20 × 10 % = 28% 100
Single equivalent discount for 28% and 5%= 28 + 5 − 28 × 5 % = 31.6% 100
Alternate method to solve this question :
Here, D_{1} = 20%, D_{2} = 10%,D_{3} = 5%
Single equivalent discount= 100 − 100 − D_{1} 100 − D_{2} 100 − D_{3} × 100 100 100 100 = 100 − 100 − 20 100 − 10 100 − 5 × 100 100 100 100 = 100 − 80 × 90 × 95 × 100 100 100 100
= 100 – 68.40 = 31.60%
 The single discount which is equivalent to successive discounts of 20%, 15% and 10% is

 32·7%
 34·2%
 36·9%
 38·8%

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Use the below formula to calculate the Equivalent single discount.
Equivalent single discount = D_{1} + D_{2} − D_{1} × D_{2} % 100
Single equivalent discount for 20 % and 15 %= 20 + 15 − 20 × 15 % = 32% 100
Single equivalent discount for 32% and 10%= 32 + 10 − 32 × 10 % = 38.8% 100 Correct Option: D
Use the below formula to calculate the Equivalent single discount.
Equivalent single discount = D_{1} + D_{2} − D_{1} × D_{2} % 100
Single equivalent discount for 20% and 15%= 20 + 15 − 20 × 15 % = 32% 100
Single equivalent discount for 32% and 10%= 32 + 10 − 32 × 10 % = 38.8% 100
Alternate method to solve this question :
Here, D_{1} = 20%, D_{2} = 15%,D_{3} = 10%
Single equivalent discount= 100 − 100 − D_{1} 100 − D_{2} 100 − D_{3} × 100 100 100 100 = 100 − 100 − 20 100 − 15 100 − 10 × 100 100 100 100 Equivalent single discount = 100 − 80 × 85 × 90 × 100 100 100 100
Hence Equivalent single discount = 100 – 61.20 = 38.80%
 A single discount equivalent to discount series 20%, 20% and 10% is

 50%
 48.4%
 42.4%
 40.4%

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Single equivalent discount for 20% and 20%
= 20 + 20 − 20 × 20 % = 36% 100
Single equivalent discount for 36% and 10%= 36 + 10 − 36 × 10 % = 42.4% 100 Correct Option: C
Single equivalent discount for 20% and 20%
= 20 + 20 − 20 × 20 % = 36% 100
Single equivalent discount for 36% and 10%= 36 + 10 − 36 × 10 % = 42.4% 100
Alternate method to solve this question := 100 − 100 − D_{1} 100 − D_{2} 100 − D_{3} × 100 100 100 100 = 100 − 100 − 20 100 − 20 100 − 10 × 100 100 100 100 = 100 − 80 × 80 × 90 × 100 100 100 100
= 100 – 57.60 = 42.40
 The difference between a discount of 35 % and two successive discounts of 20 % on a certain bill was ₹ 22. The amount of the bill was

 ₹ 200
 ₹ 220
 ₹ 1,100
 ₹ 2,200

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Single equivalent discount of two successive discounts of 20 % each
= 20 + 20 − 20 × 20 % 100 Correct Option: D
Single equivalent discount of two successive discounts of 20% each
= 20 + 20 − 20 × 20 % 100
= 36%
If the amount of the bill be A, then
∴ (36 – 35)% of A = 22⇒ A = 22 100
⇒ A = ₹ 2200
 The single discount equivalent to two successive discounts of 20% and 5% is

 24%
 25%
 22%
 23%

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Equivalent single discount = x + y − xy % 100 Correct Option: A
Equivalent single discount = x + y − xy % 100 Equivalent single discount = 20 + 5 − 20 × 5 % 100
Equivalent single discount = (25 – 1)% = 24%