If one needs to score 34% to pass a test, the pass marks out of 40 would be:

 

Let 36 is p% of 80

=> p x 80/100 = 36

=> p = 36 x 10/8 = 45.

Let the number of students = 100

Number of students who failed in one or more subjects = 14 + 22 + 18 = 54%

The percentage of students who passed in both the subjects = 100 - 54 = 46%.

The discount offered by showroom = 18%

Raghu purchased at Rs. 54540

Then,

The marked price is given by 

54540 x 100/82

=~ Rs. 66,512

5% of 4000

= 5 x 4000/100

= 5 x 40

= 200

Hence, 5% of 4000 = 200.

Let the total length of the pencil = x cms

From the given data,

'x/8' is black

Remaining part = x - x/8 = 7x/8

1/2 of 7x/8 is white

=> 7x/16 is white (Remaining part is 7x/16)

And given that the remaining part is blue and is 3 1/2 cm = 7/2 = 3.5 cm

That remaining part = 7x/16

Therefore,

7x/16 = 7/2

x = 16/2 = 8

Hence, the total length of the pencil = x = 8 cm.

Let the cost price of each mango be Rs. 1

So 50 mangoes costs = Rs. 50

20% Profit on Selling Price of 10 mangoes = Rs. 12 

30% Profit on Selling Price of 20 mangoes = Rs. 26

Total = Rs. 38

Loss = 50 - 38 = 12

Loss% = (12/50) x 100 = 24%.

The given sentence 21 is 35 of what number means that 

21 is 35 % of what number

Let that number be P

=> 35P/100 = 21

35P = 2100

P = 2100/35 = 300/5 = 60

Hence, 21 is 35 of 60.

Mass of zinc ore = 8000 kg

Mass of metal = 60% of 8000 = 4800 kg

Mass of silver in metal = 3/4 x 4800/100 = 36 kg

Mass of zinc = 4800 - 36 = 4764 kg.