GATE Questions

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What has one eye yet cannot see is An Eye of a Needle.

A needle has an eye through which we thread it but it is not for seeing.

LCM of (80, 85, 90) can be found by prime factorizing them.

80 → 2 × 2 × 2 × 2 × 5

85 → 17 × 5

90 → 2 × 3 × 3 × 5

L.C.M of (80,85,90) = 2 × 2 x 2 × 2 × 3 × 3 × 5 × 17

= 16 x 9 x 85

= 144 x 85

= 12240

L.C.M of (80,85,90) = 12240.

We know that   Speed=distancetime 

distance= speed * time

⇒ d=40×518×9

   d= 100 mts.

Quantity of fruit juice in the mixture = 70 - [70 x (10/100) ]= 63 litres.

After adding water, juice would form 87.5% of the mixture.

Hence, if quantity of mixture after adding x liters of water, [(87.5) /100 ]*x = 63 => x = 72 

Hence 72 - 70 = 2 litres of water must be added.

Given the ratio of efficiencies of P, Q & R are 3 : 8 : 5

Let the efficiencies of P, Q & R be 3x, 8x and 5x respectively

They can do work for 12 days.

=> Total work = 12 x 16x = 192x

Now, the required time taken by Q to complete the job alone = 162x8x = 24days.

From the above formula i.e (m1 x t1/w1) = (m2 x t2/w2)

so, [(34 x 8 x 9)/(2/5)] = [(M x 6 x 9)/(3/5)]

so, M = 136 men

Number of men to be added to finish the work = 136-34 = 102 men.

From the given diagram,

Tank 10 will be first filled because from tank 1 it will go through tank 4 and tank 10.

If a number to be divisile by 88, it should be divisible by both "8" and "11"

Check for '8' :
For a number to be divisible by "8", the last 3-digit should be divisible by "8"
Here 72x23y --> last 3-digit is '23y'
So y=2 [ (i.e) 232 is absolutely divisible by "8"]

Chech for '11' :
For a number to be divisible by "11" , sum of odd digits - sum of even digits should be divisible by "11"
(7 + x + 3) - (2 + 2 + y)
(7 + x + 3) - (2 + 2 + 2)
(10 + x) - 6 should be divisible by "11"
for x = 7
=> 17 - 6 = 11 [ which is absolutely divisible by "11"]

So x = 7 , y= 2.