DoubtNut Interview Questions, Process, and Tips

8:20

One day’s work of A, B and C = (1/24 + 1/30 + 1/40) = 1/10.

C leaves 4 days before completion of the work, which means only A and B work during the last 4 days.

Work done by A and B together in the last 4 days = 4 (1/24 + 1/30) = 3/10.

Remaining Work = 7/10, which was done by A,B and C in the initial number of days.

Number of days required for this initial work = 7 days.

Thus, the total numbers of days required = 4 + 7 = 11 days.

132

135 is wrong because from starting difference between 7 after that 9 after 11 ,13,17 and so on

₹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

B

90 hours

14

C

Father’s sister

Answer: 3121 gold coins
Let total no of coins be M
Let the disbursement D to each son:

D1 = 1 + (M – 1)/5 = (M + 4)/5
D2 = 1 + ( M – D1 -1)/5 = (D1) * 4/5
D3= (D2) * 4/5
D4= (D3) * 4/5
D5= (D4) * 4/5
Total disbursements to sons=
= ∑D= (M+4)*1/5[ 1+4/5+(4/5)(4/5)+ (4/5)(4/5)(4/5)+(4/5)(4/5)(4/5)(4/5) ]
= (2101/3125)*(M+4)
Thus balance left for daughters =M-{(2101/3125)*(M+4)}
=(1024M-8404)/3125
This balance should be a positive integer ( assuming M and all disbursements are full coins )
Thus 1024M-8404 should be a multiple of 3125….so….
1024M – 8404 = N*3125 where N is an integer
Using Python code:
n=int(input(“Enter num n: “))
X=int()
a=int()
a=0
X=’ ‘
for a in range(0,n+1):
a=a+1
X= (3125*a + 8404)/1024
if (3125*a + 8404)% 1024== 0:
print(X,a)
Enter num n: 10000
3121.0 1020
6246.0 2044
9371.0 3068
12496.0 4092
15621.0 5116
18746.0 6140
21871.0 7164
24996.0 8188
28121.0 9212
We get minimum value of N = 1021 and M = 3121 gold coins

Day 1: 30-3ft = 27+2ft = 29
Day 8: 23 jumps 3ft = 20 slips 2ft = 22
Day 16: 13 jumps 3ft = 10 slips 2ft = 12
Day 24: 3 jumps 3ft = Out?

9 years
Bcz 3×3=9
5×3=15
7×3=21
Total = 45
Avg of this 45/3 = 15