Costain Interview Questions, Process, and Tips

15/46=0.32

427 is the answer
Because
385 means (3+5=8) or (8-3=5) ,
462 means (4+2=6) or (6-2=4) ,
572 means (5+2=7) or (7-5=2) ,
396 means (6+3=9) or (9-3=6) ,
671 means (6+1=7) or (7-6=1) ,
264 means (4+2=6) or (6-2=4) ,
but only 427 is the number in which if we do addition of any of its two digits (e.g 4+2 or 4+7) then its answer doesn’t come 3rd digit
like if we do 4+2 then answer will be 6 so the number should be 426 but it is not
or if we do 7-4 then answer will be 3 (not 2)
so the right answer is 427

X filling rate is 1/18 or 4/72 per hour

Y filling rate is 1/24 or 3/72 per hour

Combined as a pair it’s 7/72 in a complete 2 hour alternating sequence

72+ 7/72 =10 sequences = 70/72 on 20 hours, The outstanding balance is just 2/72

So at 20.5 hours with X turn filling is 100% complete with 72/72

Answer: It will take 20.5 hours to completely fill this tank.

Analysis of measured filling process, from X = 42/72 share & from Y = 30/72 share

(x+2)+(x)+(x-2)
X+2+x+x-2=18
3x=18
X=6
The 3digit number is 864

For optimal size of a project team..
the % increase in staff size should be “Zero”
reason:
additional member directly proportional to increase in
staff size..

b

Relative speed = 60 + 90 = 150 km/hr.

= 150 x 5/18 = 125/3 m/sec.

Distance covered = 1.10 + 0.9 = 2 km = 2000 m.

Required time = 2000 x 3/125 = 48 sec.

11

₹1 today increases to (1+1/8) = 9/8 after 1year.

After 2 years it increases to 9/8 of 9/8 = (9/8)^2 =81/64 times.

Hence ₹64000 increase to 64000×81/64 =₹81000

8