Let the number be N.

According to the question,
(78 - 59)% of N = 323

Correct Option: A

Let the number be N.

According to the question,
(78 - 59)% of N = 323
⇒ (19 x N)/100 = 323
∴ N = (323 x 100)/19 = 1700
∴ 62% of 1700 = (62/100) x 1700 = 1054

Here, a = 20%
Required percentage loss = [a / (100 + a)] x 100%

Correct Option: A

Here, a = 20%
Required percentage loss = [a / (100 + a)] x 100%
= [20/(100 + 20)] x 100%
= (20/120) x 100%
= 16²/₃%

Require number = 1240 x (25/100)

Correct Option: C

Require number = 1240 x (25/100)
= 310

Let a student was awarded in exam = N marks
According to the question,
After re-evaluation his score
⇒ N - N x (40/100) = 96

Correct Option: E

Let a student was awarded in exam = N marks
According to the question,
After re-evaluation his score
⇒ N - N x (40/100) = 96
⇒ N - 2N/5 = 96
⇒ 5N - 2N/5 = 96
⇒ 3N/5 = 96
⇒ N = (5 x 96)/3 = 5 x 32
⇒ N = 160
So, a student was awarded by 160 marks in examination
∴ Reduced marks after re-evaluation = 160 - 96 = 64

Increase in percentage of longer pipe compared to shorter pipe
= [(70 - 30)/30] x 100%

Correct Option: B

Increase in percentage of longer pipe compared to shorter pipe
= [(70 - 30)/30] x 100%
= (40/30) x 100%
= 400/3 %