Quantitative Aptitude - Arithmetic Ability Questions

Multiples of 3 below 20 are 3, 6, 9, 12, 15, 18
Multiples of 5 below 20 are 5, 10, 15, 20
Required number of possibilities = 10
Total number of possibilities = 20
Required probability = 10/20 = 1/2.

Let the number be x. Then, x - 3x/5 = 50  <=>  x = (50 * 5) / 2 = 125..

i=j/m

PV
= FV (1+  i)^-n

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%.

Let the second & third numbers are 2x & 3x respectively.
ATQ,
5x*6x = 4320
30*x*x = 4320
x*x = 144
x=12
Hence, second number = 5x = 5*12 = 60
Third number = 6x = 6*12 = 72
Ratio of first & second number = ¾
Hence, first number = ( ¾)*60 = 45
Sum of these 3 numbers = 60+72+45 = 177

Ans. 
Let B’s investment = x rs.
∴ A’s investment =( x + 1200) rs.
Ratio of the profits of A and B = (x+1200)*(15+4):x*15 = {19(x+1200)}:15x
Now,let the total profit of A =y
∴ total profit of B = (y-280)
But total profit = 1240
⇒y+(y-280)=1240
⇒2y=1520
⇒y= 760
∴profit of A = 760rs.
Profit of B = 760-280=480 rs.
Ratio of profits= 760:480 = 19:12
According to the question,

19(x+1200)/15x = 19/12

12x+14400 = 15x

⇒3x = 14400
⇒x = 4800 rs.
⇒investment of A = 4800+1200
                          = 6000 rs.