Quantitative Aptitude - Arithmetic Ability Questions

Let the numbers be x and 4x. Then,  x×4x=84×21 ⇔ x2=84×214⇔ x=21 

Hence Larger Number = 4x = 84

5% is the rate of interest. 20% of the interest amount is paid as tax.

i.e  80% of the interest amount stays back.

 if we compute the rate of interest as 80% of 5% = 4% p.a., we will get the same value.

The interest accrued for 3 years in compound interest = 3 x simple interest on principal + 3 x interest on simple interest + 1 x interest on interest on interest.

= 3 x (200) + 3 x (8) + 1 x 0.32 =600 + 24 + 0.32 = 624.32

The amount at the end of 3 years = 5000 + 624.32 = 5624.32

Let the number of workers be x.

Now, Using work equivalence method,

X + (X-1) + (X-2)+ . . . . + 1 = X *55% of X

=> [X * (X+1)] / 2 = X * (55X/100)    [because, Series is in AP. Sum of AP = {No. of terms (first term+ last term)/2} ]

Therefore, X = 10 

Present Worth

=P1+R1002

=1691+41002

= Rs.156.25

Let the number of boys and girls be 8x and 5x.
Total number of students = 13x = 13 * 32 = 416.

Let the required no of hectares be x. Then 

More men, More hectares      (Direct proportion)

More days, More hectares      (Direct proportion)

 Men8 : 36Days24:30⋮⋮ 80 :x

=> ( 8 * 24 * x) = (36 * 30 * 80)

=>  x= 450