Quantitative Aptitude - Arithmetic Ability Questions

We know that, After every 400 years, the same day occurs.

Thus, if 9th August 2016 is Saturday, before 400 years i.e., on 9th August 1616 has to be Saturday.

General Formula:

Final or reduced concentration = initial concentration x 1-amount being replaced in each operationtotal amountn

where n is the number of times the same operation is being repeated. The "amount being replaced" could be pure or mixture as per the case. similarly ,"total amount" could also be either pure or mixture. Here amount being replaced denotes the quantity which is to be withdrawn in each time.

Therefore,    50×1-5503

= 36.45 L

Let Veena paid x,
so Akshitha paid 2x/3 , and Lasya paid 2x,
So total bill paid is given by
x+(2x/3) +2x = 1, we get
i.e. x = 3/11

Given ratio of pens and pencils = 3 :2

Number of Pens = 3x

Number of Pencils = 2x

Average number of pencils & Pens = 3x + 2x2 = 180

5x = 360

=> x = 72

Hence, the number of pencils = 2x = 72 x 2 = 144.

Let the age of the daughter today be ‘x’ years.
Mother’s age today = 3x years
After 10 years, we have
3x + 10 = 2(x + 10)
x = 10 years.

In the same time, they cover 110 km and 90 km respectively.

Therefore, Ratio of their speeds = 110 : 90 = 11 : 9

Speed in downstream = 96/8 = 12 kmph

Speed of current = 4 km/hr

Speed of the boatman in still water = 12 – 4 = 8 kmph

Speed in upstream = 8 – 4 = 4 kmph

Time taken to cover 8 km upstream = 8/4 = 2 hours.