Quantitative Aptitude - Arithmetic Ability Questions

let ABCD be the given parallelogram 

area of parallelogram ABCD = 2 x (area of triangle ABC) 

now a = 30m, b = 14m and c = 40m

 s=1/2 x (30+14+40) = 42 

Area of triangle ABC = ss-as-bs-c  

= 4212282= 168sq m 

area of parallelogram ABCD = 2 x 168 = 336 sq m

Let original length = x and original breadth = y.

Original area = xy. 

New length = x/2 and New breadth=3y 

New area = 32xy 

Therefore,  Increase in area = New area-original area = 32xy-xy=12xy 

Therefore,  Increase % = increase in area original area*100=12xyxy*100=50 %

87)13601(156
       87
       -----
       490
       435
        -----
        551
        522
         -----
         29
         -----
Required number is 29.

As the ratio of their present ages is 3 : 4 , let their present ages be 3X and 4X.

So, 5 years ago, as the ratio of their ages was 5 : 7, we can write  (3x-5) : (4x-5) = 5 : 7. Solving, we get X = 10. Hence, their present ages are 3X = 30 and 4X = 40