Quantitative Aptitude - Arithmetic Ability Questions

The hands of a clock point in opposite directions (in the same straight line) 11 times in every
12 hours. (Because between 5 and 7 they point in opposite directions at 6 o'clcok only).
So, in a day, the hands point in the opposite directions 22 times

Rate of her upstream = 12/2.5 = 4.8 km/hr

Then, ATQ

Rate of downstream = 4.8 x 3 = 14.4 km/hr

Hence, the distance she covers downstream in 5 hrs = 14.4 x 5 = 72 kms.

Let the present age of Pinky be x years

Then the age of Mary is x - 12 years

After 3 years,

Ratio of  MaryPinky = x - 9x + 3 = 58

8x - 72 = 5x +15

=> 3x = 87

=> x = 29

=> Age of Pinky = 29 years

=> Age of Mary = 29 - 12 = 17 years

Present age of Sam = 29 + 17 = 46

Before 15 years Sam age = 46 - 15 = 31 years.

A team of 6 members has to be selected from the 10 players. This can be done in 10C6 or 210 ways.

Now, the captain can be selected from these 6 players in 6 ways.
Therefore, total ways the selection can be made is 210×6= 1260

Profit would be maximum if watches are brought for Rs. 200 and sold for Rs. 425
Profit = Rs. (425 - 200) = Rs. 225
Profit of 9 watches = Rs. 225 x 9 = Rs.2,025.

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

0.204×420.07×3.4=8568238=36 =6

As A1 speaks always after A2, they can speak only in  1st  to 9th places and 

A2 can speak in 2nd to 10 the places only when A1 speaks in 1st place 

A2 can speak in 9 places the remaining 

 A3, A4, A5,...A10  has no restriction. So, they can speak in 9.8! ways. i.e

when A2 speaks in the first place, the number of ways they can speak is 9.8!.

When A2 speaks in second place, the number of ways they can speak is  8.8!.

When A2 speaks in third place, the number of ways they can speak is  7.8!. When A2 speaks in the ninth place, the number of ways they can speak is 1.8!

Therefore,Total Number of ways they can  speak = (9+8+7+6+5+4+3+2+1) 8! = 92(9+1)8! = 10!/2