Quantitative Aptitude - Arithmetic Ability Questions

We know that I = PTR/100
=> P = 20250/4.5 = 4500
Now, new Interest at 5% = 4500x1x5/100 = 225
Now the additional amount = 225 - 202.5 = Rs. 22.5

Let the Father be x years when he died

Average Age 10 years ago be A

Total Age 10 years ago = 6*A

Total Age after 10 years(Just before father's Death) = 6A + 6*10 = 6A + 60

Father Died and Baby was born => the Total number of people in the family is Same (6)
Baby born today so age of baby = 0

(6A +60 - x)/6 = 6A/6
=> A + 10 -(x/6) = A
=> x/6 = 10
=> x = 60

Therefore we can conclude that the father was 60 years old when he died.

Population afer 3 years = 64000 * (1 +  5/(2 *100) )^3 = (64000 * 41/40 * 41/40 * 41/40 ) = 68921..

Let p% of a day is 3 hrs.

We know that a day has 24 hrs.

=> p x 24/100 = 3

=> p = 300/24

=> p = 12.5%

Hence, 3 hrs is 12.5% of a day.

Less Cogs  more turns and less time  less turns

$$\begin{gathered} Cogs Time Turns \\ A 54 45 80 \\ B 32 8 ? \end{gathered}$$

Number of turns required=80 × 54/32 × 8/45  = 24 times

Work done by the waste pipe in 1 minute =115-120+124=115-11120 = -140 [-ve sign means emptying]

Volume of 140part = 3 gallons

Volume of whole = (3 x 40) gallons = 120 gallons.