Quantitative Aptitude - Arithmetic Ability Questions

Given in the question that, there are 7 boys and 6 girls. 

Team members = 5

Now, required number of ways in which a team of 5 having atleast 3 girls in the team = 

$$\begin{gathered} 6C3 x 7C2 + 6C4 x 7C1 + 6C5 \\ = 6x5x43x2x1 x 7x62x1 + 6x5x4x34x3x2x1 x 7 + 6x5x4x3x25x4x3x2x1 \\ = 420 + 105 + 6 \\ = 531. \end{gathered}$$

Speed of streamer = 4.5 km/hrSpeed of water = 1.5 km/hr

Downstream speed = 4.5+1.5 = 6 km/hr

Upstream speed = 4.5 -1.5 = 3 km/hr

Average Speed = (6 X 3) / 4.5 = 4km/hr

Let the cost price of A as well as B is 100 Rs.
Then, ATQ:
Selling Price of A = 100+40 = 140
And Selling Price of B = 140 - (140*0.2) = 140 - 28 = 112
Total selling price = 140+112 = 252 Rs.
Total Cost price = Rs. 200
So by taking cost price = 100 Rs.
Total profit = 52 Rs.
Total profit will be Rs. 156 when cost price = (100/52)*156 = Rs. 300.

T = (100 x I)/ (P x r)

i=j/m

Given that three athletes can complete one round around a circular field in 16, 24 and 36 min respectively.

Now, required time after which they met for the first time = LCM of (16, 24 & 36) min

Now, LCM of 16, 24, 36 = 144 minutes = 2 hrs 24 min.

Amount = Rs. (30000 + 4347) = Rs. 34347.

Let the time be n years.

Then, 30000*(1+7/100)^n=34347

n= 2 years

The number of ways in which the letters of the word RAILINGS can be arranged such that R & S always come together is

Count R & S as only 1 space or letter so that RS or SR can be arranged => 7! x 2!

But in the word RAILINGS, I repeated for 2 times => 7! x 2!/2! = 7! ways = 5040 ways.