Quantitative Aptitude - Arithmetic Ability Questions

Let the list price be Rs.100. 

Therefore, the retailer is buying the products at Rs.60 and selling it to the customer at Rs.75, earning a profit of Rs.15.

Therefore, his percentage is = 1560x100 = 25%

Since Pooja and Shipra are twins so their ages be same. Let their ages be x and age of Mounika be y , then 

           x+x = y    -------(1) 

 and   x-3y-3=27⇒7x-2y=15 

Now, from  equation (1), 

         7x - 4x = 15  =>  x = 5

So the age of Shipra 3 years hence will be 5+3 = 8 years

As we know we have 10 letter and 10 different address and one more information given that exactly 9 letter will at the correct address....so the remaining one letter automatically reach to their correct address
P(E) = favorable outcomes /total outcomes
Here favorable outcomes are '0'.
So probability is '0'.

Let the speed of the man in still water = p kmph

Speed of the current = s kmph

Now, according to the questions

(p + s) x 10 = (p - s) x 15

2p + 2s = 3p - 3s

=> p : s = 5 : 1

Hence, ratio of his speed to that of current = 5:1.

Let work done by 1 man in i day be m

and Let work done by 1 boy in 1 day be b

From the given data,

4(5m + 3b) = 23

20m + 12b = 23....(1)

2(3m + 2b) = 7

6m + 4b = 7 ....(2)

By solving (1) & (2), we get

m = 1, b = 1/4

Let the number of required boys = n

6(7 1 + n x 1/4) = 45

=> n = 2.

Let the total work be 'W'

As per the given information,

P can complete the work 'W' in 24 days.

=> one day work of P = W/24

And also given that,

The time taken by P to complete one-third of work is equal to time taken by Q to complete half of the work

=> PW/3 = QW/2

=> P's

1 day =    W/24

   ?    =      W/3

=>  ?  = 24W/3W  = 8

=> QW/2 = 8 days

=> Q alone can complete the work W in 16 days

=> P + Q can complete the work in

1/24 + 1/16 = 5/48

=> 48/5 days = 9 3/5 days.