Here, r = 20% and r₁ = 15%
Required profit per cent =[ r(100 - r₁)/100] - r₁
= [20(100 - 15)/100] - 15

Correct Option: B

Here, r = 20% and r₁ = 15%
Required profit per cent =[ r(100 - r₁)/100] - r₁
= [20(100 - 15)/100] - 15
= 17 - 15
= 2%

∵ Single discount equivalent to 36% and 4%
= 36 + 4 - {(36 x 4)/100} = 38.56

Correct Option: D

∵ Single discount equivalent to 36% and 4%
= 36 + 4 - {(36 x 4)/100} = 38.56

∴ Required difference
= {(40 - 38.56) x 500}/100 = 1.44 x 5 = ₹ 7.20

∵ Marked price of a shirt = ₹ 320
Discount on a shirt = 320 x 25/100 = ₹ 80

Correct Option: D

∵ Marked price of a shirt = ₹ 320
Discount on a shirt = 320 x 25/100 = ₹ 80

∴ Number of shirts has to be purchased to get a rebate of ₹ 400 = 400/80 = 5

Let the marked price of item = ₹ N
∴ {(100 - 14) /100 } of N = 645

Correct Option: C

Let the marked price of item = ₹ N
∴ {(100 - 14) /100 } of N = 645
⇒ N = (645 x 100)/86 = ₹ 750

Here, r₁ = 10 %, r₂ = 20% and r₃ = 30%
∴ Required discount
= [1 - (1 - r₁/100) (1 - r₂/100) (1 - r₃/100)] x 100%

Correct Option: B

Here, r₁ = 10 %, r₂ = 20% and r₃ = 30%
∴ Required discount
= [1 - (1 - r₁/100) (1 - r₂/100) (1 - r₃/100)] x 100%
= [1 - (1 -10/100) (1 - 20/100) (1 - 30/100)] x 100%
= {1 - (9/10) x (4/5) x (7/10)} x 100%
= (1 - 0.504) x 100% = 49.6%