Quantitative Aptitude - Arithmetic Ability Questions

2(A+B+C)'s 1 day work = 1/30 + 1/24 + 1/20 = 1/8

=>(A+B+C)'s  1 day's work= 1/16

work done by A,B and C in 10 days=10/16 = 5/8

Remaining work= 3/8

A's 1 day's work= 116-124=148

Now, 1/48 work is done by A in 1 day.

 So, 3/8 work  wil be done by A in =48 x (3/8) = 18 days

Angle traced by hour hand in 17/2 hrs = 36012×172o = 255 

Angle traced by min hand in 30 min = 36060×30o = 180 

Therefore,  Required angle = (255 - 180) = 75o

Step 1 :2x + 5y

Step 2 :3(2x + 5y) = 6x + 15y

Step 3 :(6x + 15y) - (x +y) = 6x + 15y - x - y (watch that last minus sign!)

This gives 5x + 14y

Note : If two trains (or bodies) start at the same time from points A and B towards each other and after crossing they take a and b sec in reaching B and A respectively, then: (A's speed) : (B's speed) = (b : a)

Therefore, Ratio of the speeds of two trains = 9:4 = 3 : 2

No. of bricks= volume of the wall/volume of 1 brick

= (800 x 600 x 22.5) / (25 x 11.25 x 6) = 6400

34×(x-2)x=(x+7)(x-10)

⇒x2-6x-280 =0 

=> x= 20   and   x=-14

 so, the acceptable values is x=20 

Therefore, Total work =(x-2)x = 18 x 20 =360 unit

 Now   360 = 30 x k         

=> k=12 days

16x + 85 = 17(x + 3)

x = 34 + 3 = 37