4 drivers: 1 hour
$\Rightarrow$  4 : 1
20 drivers: 5 hours
$\Rightarrow$  20 : 5 $\Rightarrow$  4 : 1
$\therefore$ Given ratios are equivalent.

Each answer: 1 Mark
Given that,
Number circles = 26
Number of hearts = 1 
Number of stars=1
$\therefore$ Number of circles: number of hearts
$\Rightarrow$  26 : 1
$\therefore$ Number of hearts: number of stars
$\Rightarrow$  1 : 1

Each Ratio: 1 Mark
Given ratio is, 5:4
$\Rightarrow \frac{5}{4}$
$=\frac{5}{4}$ x $\frac{25}{25}$
=$\frac{125}{100}$
=125 $\%$
Now,
$9:25=\frac{9}{25}$ x $\frac{4}{4}$
$=\frac{36}{100}$
$=36\%$

Concept: 1 Mark
Steps: 1 Mark
Answer: 1 Mark
Let Nishu's pocket money be $n$
Given, she saves 10% of her pocket money. 
$\Rightarrow$ 10% of n = ₹ 120
$\Rightarrow \frac{10}{100}\times n=120$
$\Rightarrow n=\frac{120\times 100}{10}$
$\Rightarrow n=1200$
So, Nishu's pocket money is ₹ 1200.

Formula: 1 Mark
Answer: 1 Mark
Given that,
Marked Price of the watch = ₹ 1250.
6% discount on MP
$\Rightarrow \frac{6}{100}\times 1250=₹75$
SP = MP - Discount.
SP = ₹ 1250 - ₹ 75.
SP = ₹ 1175.

The selling price of the watch is  ₹ 1175.

Steps: 1 Mark
Answer: 1 Mark
Total number of students = 860
 Number of students who study Sanskrit = 35%
 Therefore, number of students who do not study Sanskrit =100% - 35% = 65%
$\therefore$  Number of students not studying Sanskrit,
$=\frac{65}{100}\times 860=559$
So, 559 students do not study Sanskrit.

Formula: 1 Mark
Steps: 1 Mark
Answer: 1 Mark
Given that,
Original price = ₹ 3,50,000.
New price = ₹ 3,70,000.
Increase in the price = ₹ 3,70,000 - ₹ 3,50,000.
$\therefore$ Increase in the price = ₹ 20,000
$Percentageincrease=\frac{Increaseintheprice}{originalprice}\times 100$
$Percentageincrease=\frac{20000}{350000}\times 100$
$Percentageincrease=5.714\%$
The price of the car went up by 5.714$\%$

Formula: 1 Mark
Steps: 1 Mark 
Answer: 1 Mark

Given, 

The number 'n' is first increased by 25$\%$. 
$25$

So, the new value of n
$=n+n\times \frac{25}{100}=n\times \frac{5}{4}$

Now, the value of is again decreased by $20$.

So, $20$ of the new value
$=n\times \frac{5}{4}\times \frac{20}{100}=n\times \frac{1}{4}$

So, the new value
$=n\times \frac{5}{4}$ - $n\times \frac{1}{4}=n$

Net percent change
$=\frac{\text{amount changed}}{\text{original value}}\times 100$

Net change = n - n = 0.
So on substituting the values we get:
Percent change = $\frac{0}{n}\times 100$ = 0
So, there is no percentage change.

Steps: 1 Mark
Application: 1 Mark 
Calculation: 1 Mark
Marks scored in the 1st test = 70
Marks scored in the 1st test = 85
Increase in marks = 1st test mark - 2nd test marks
Increase in marks = 85 - 70 = 15
Increase in percentage
$=\left(\frac{Increase}{Originalmarks}\right)\times 100$
Increase in percentage
$=\left(\frac{15}{70}\right)\times 100$ = 21.42 %

Concept: 1 Mark
Application: 1 Mark 
Each Answer: 1 Mark
Given that
Amina bought a book for ₹ 275.
So the Cost price, CP = ₹ 275.
$Loss\%=15\%$
$Loss=15\%of275$
$Loss=\frac{15}{100}\times 275$
$Loss=\frac{4125}{100}$
$Loss=41.25$
$Sellingprice=Costprice-Loss$
$Sellingprice=275-41.25$
$Sellingprice=₹233.75$
Hence she sold it at ₹ 233.75.
If she has sold at ₹ 286,
The selling price, SP = ₹ 286
Profit = SP - CP
$\therefore$ On substituting the values we get, Profit = (286 - 275) = ₹ 11
Now, Profit % $=\frac{profit}{CostPrice}\times 100$
Profit % $=\frac{11}{275}\times 100=4$
$\therefore$ Had she sold it at ₹ 286 her profit% would have been 4%.