Percentage
- In the annual examination Mahuya got 10% less marks than Supriyo in Mathematics. Mahuya got 81 marks. The marks of Supriyo are
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Let marks obtained by Supriyo = x
∴ 9x = 81 10 ⇒ x = 81 × 10 = 90 9 Correct Option: A
Let marks obtained by Supriyo = x
∴ 9x = 81 10 ⇒ x = 81 × 10 = 90 9
- A student has to secure 40% marks to pass. He gets 90 marks and fails by 10 marks. Maximum marks are :
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Let the maximum marks be x.
According to the question,
40% of x = 90 + 10⇒ x = 100 × 100 = 250 40
Aliter : Using Rule 24,
a = 40%, b = 90, c = 10
Maximum marks= (b + c) × 100 a = (90 + 10) × 100 = 250 40 Correct Option: C
Let the maximum marks be x.
According to the question,
40% of x = 90 + 10⇒ x = 100 × 100 = 250 40
Aliter : Using Rule 24,
a = 40%, b = 90, c = 10
Maximum marks= (b + c) × 100 a = (90 + 10) × 100 = 250 40
- In an examination, 65% of the students passed in Mathematics, 48% passed in Physics and 30% passed in both. How much percent of students failed in both the subjects ?
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n (M) = 65, n (P) = 48, n(M∩P) = 30
∴ n(M∪P)= n(M) + n(P) – n(M∩P)
= 65 + 48 – 30 = 83
∴ Per cent of students passed = 83
∴ Per cent of students failed= 17
Method 2 :
Students passed only in Math
= 65 – 30 = 35%
Students passed only in Physics
= 48 – 30 = 18%
∴ Total passing %
= 35 + 18 + 30 = 83%
∴ Failed = 100 – 83 = 17%Correct Option: A
n (M) = 65, n (P) = 48, n(M∩P) = 30
∴ n(M∪P)= n(M) + n(P) – n(M∩P)
= 65 + 48 – 30 = 83
∴ Per cent of students passed = 83
∴ Per cent of students failed= 17
Method 2 :
Students passed only in Math
= 65 – 30 = 35%
Students passed only in Physics
= 48 – 30 = 18%
∴ Total passing %
= 35 + 18 + 30 = 83%
∴ Failed = 100 – 83 = 17%
- The cost of an article worth 100 is increased by 10% first and again increased by 10%. The total increase in rupees is
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Using Rule 7,
Percentage effect= 
10 + 10 + 10 × 10 
% = 21% 100
∴ Increase = ₹21Correct Option: B
Using Rule 7,
Percentage effect= 10 + 10 + 10 × 10 % = 21% 100
∴ Increase = ₹21
- The price of an article was decreased by 10% and again reduced by 10%. By what per cent should the price have been reduced once, in order to produce the same effect as these two successive reductions ?
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Using Rule 6,
A single equivalent reduction to reduction series of x%, y%= x + y - xy % 100 = 10 + 10 - 10 × 10 % 100
= (20 - 1)% = 19%Correct Option: B
Using Rule 6,
A single equivalent reduction to reduction series of x%, y%= x + y - xy % 100 = 10 + 10 - 10 × 10 % 100
= (20 - 1)% = 19%
