Quantitative Aptitude - Arithmetic Ability Questions

Less toys, Less Price (Direct Proportion)
So, let the price be Rs. x
then,

             23:12::276:x    => x=(276*12)/23

                                    => x=144

So price of 12 toys will be Rs. 144

Let M, N and O worked together for x days.

From the given data,
M alone worked for 8 days
M,N,O worked for x days
N, O worked for 1 day

But given that
M alone can complete the work in 18 days
N alone can complete the work in 36 days
O alone can complete the work in 54 days

The total work can be the LCM of 18, 6, 54 = 108 units

M's 1 day work = 108/18 = 6 units
N's 1 day work = 108/36 = 3 units
O's 1 day work = 108/54 = 2 units

Now, the equation is
8 x 6 + 11x + 5 x 1 = 108
48 + 11x + 5 = 108
11x = 103 - 48
11x = 55
x = 5 days.

Hence, all M,N and O together worked for 5 days.

It is in the form of a2-b2a-b = a+ba-ba-b = a+b

Here a = 3.39   b = 2.61 

 = 3.39 + 2.61 = 6.

Here distance d = 800 mts

speed s = 63 - 3 = 60 kmph = 60 x 5/18 m/s

time t = 800x1860x5= 48 sec.

Let 28x+1426=3×718

Then 28x=2154-1426 

⇒28x=728 ⇒x=26

∴x=676

Let Mohan present age = p

ATQ,

5/6 x p = p - 5

p = 30

His wifes age = 30 - 3 = 27 yrs.

If Jason is on th ecouncil,this reduces the selction pool to only 13 people,out of which we still need to select 4.

So, 13C4 = 715

A number is divisible by 9 only if the sum of the digits of the number is divisible by 9.

Here 86236 = 8 + 6 + 2 + 3 + 6 = 25

We must add 2 to 25 to become 27 which is divisible by 9.