Quantitative Aptitude - Arithmetic Ability Questions

Let S be the sample space. Then,
n(s) = number of ways of drawing 4 pearls out of 14

= C414 ways = 14×13×12×114×3×2×1= 1001

Let E be the event of drawing 4 pearls of the same colour.
Then, E = event of drawing (4 pearls out of 5) or (4 pearls out of 4) or (4 pearls out of 5)

  ⇒C15+ C44+ C15 = 5+1+5 =11

 P(E) = n(E)n(S)=111001=191  

 Required probability = 1-191=9091

I = (P x T x R) /100

Total number of exams written by 100 students = 48 + 45 + 38 = 131
Now let us say x members are writing only 1 exam, y members are writing only 2 exams, z members are writing only 3 exams.
Therefore, x + 2y + 3z = 131 also x + y + z = 100.
Given that z = 5. So x + 2y = 116 and x + y = 95.
Solving we get y = 21.
So 21 members are writing exactly 2 exams.

Given digits are 0, 4, 2, 6

Required 4 digit number should be greater than 6000.

So, first digit must be 6 only and the remaining three places can be filled by one of all the four digits.

This can be done by

1x4x4x4 = 64

Greater than 6000 means 6000 should not be there.

Hence, 64 - 1 = 63.

Sum = Rs.(50*100)/2*5=Rs.500

Amount=Rs.[500*(1+5/100)2]

= Rs. 551.25

 C.I = Rs.(551.25-500)= Rs.51.25

Let Althaf lent Rs. A at 14% per year.
Hence, Money lent at 12% = (1500-A);
Given, total interest = Rs. 186.
{(A x 14x 1)/100} + {[(1500-A) x 12 x 1/100]} = 186;
14A/100 + (18000 -12A)/100 = 186;
14A + 18000 - 12A = 186x100;
2A = 18600-18000;
A = 600/2 = Rs. 300.
Hence, money lent at 12% = 1500-300 = Rs. 1200.

Let t be the usual time. If the usual rate is 1 unit, then the unusual rate is 6/7.
Balance by the distance,
1 x t = (6/7)(t + 30)
7t = 6(t + 30)
we get t as,
t = 180 minutes = 3 hrs.