Question : Successive discounts of $p$% and $q$% on a catalogue price of an article is equivalent to a single discount of:

Option 1: $\left(p -q + \frac{pq}{100} \right )$%

Option 2: $\left(p - q - \frac{pq}{100} \right )$%

Option 3: $\left(p + q - \frac{pq}{100} \right )$%

Option 4: $\left(p + q + \frac{pq}{100} \right )$%

Question : From 1980 to 1990, the population of the country increased by 20%. From 1990 to 2000, the population of the country increased by 20%. Over 2000-2010, the population of the country increased by 20%. Then, the overall increased population (in percentage) of the country from 1980 to 2010 was:

Option 1: 72.2%

Option 2: 60%

Option 3: 72.8%

Option 4: 62.8%

Question : If A borrowed Rs. $P$ at $x$% and B borrowed Rs. $Q (> P)$ at $y$% per annum in simple interest at the same time, then the amount of their debts will be equal after:

Option 1: $100(\frac{Q-P}{Px-Qy})$

Option 2: $100(\frac{Px-Qy}{Q-P})$

Option 3: $100(\frac{Px-Qy}{P-Q})$

Option 4: $100(\frac{P-Q}{Px-Qy})$

Question : A mask manufacturing company manufactured an ‘$x$’ number of masks in 2018. It increased its manufacturing capacity by 30% in 2019 and further increased its manufacturing by 15% in 2020. In 2021, due to the machinery breakdown, its manufacturing declined by 40%. What is the value of ‘X’ if it manufactured 179400 masks in 2021?

Option 1: 180000

Option 2: 230000

Option 3: 200000

Option 4: 210000

Question : A water tap fills a tub in '$p$' hours and a sink at the bottom empties it in '$q$' hours. If $p < q$, both tap and sink are open, and the tank is filled in '$r$' hours, then:

Option 1: $\frac{1}{r}$ = $\frac{1}{p}+\frac{1}{q}$

Option 2: $\frac{1}{r}$ = $\frac{1}{p}-\frac{1}{q}$

Option 3: $r = p + q$

Option 4: $r = p - q$