Arithmetic Aptitude MCQ (Multiple Choice Questions)

The correct answer is (C) 100%
Step by step Solution:
We solve the problem by assuming that the original cost price be CP and the selling price be SP. Now, we have the profit (p), we have,
p = SP – CP ⇒ (1)
It is given in the problem that on doubling the selling price, the profit triples, we have,
3p = 2SP – CP ⇒ (2)
Now, we need to find the profit percent given by

\frac{S p-C p}{C p} \times 100

We need to find SP in terms of CP to find the profit percent. We use equations (1) and (2) and solve them to find SP in terms of CP. Firstly, we subtract (1) from (2),
we get ⇒ 3p-p = SP
2p = SP ⇒ (A)
Putting this in (1), we get,
p = 2p – CP
p = CP ⇒ (B)
From (A) and (B), we get that SP = 2CP. Now, we put this in the formula of profit percentage given by 

\frac{S p-C p}{C p} \times 100

We get,

\frac{2C p-C p}{C p} \times 100

The correct answer is x=16 units.
Step by Step Solution

We have 3 elements here cost price (CP), selling price (SP), and profit percentage (Profit%).
So the equations relating them are:

Profit = SP-CP (for loss its CP-SP)

Profit% =\frac{\text { (selling price – cost price) }}{\text { cost price }} \times 100

Since we don’t know the cost of the article it is ok to assume a value initially.

Let the Cost Price of each article = 1 unit.
Cost Price of 20 articles = 20 units
Selling Price of x articles=CP of 20 articles ⇒ 20 units
Selling Price of 1 article = 20/x

using formula Profit% for 1 article as profit% is a constant for each article.

Profit% =\frac{\text { (selling price – cost price) }}{\text { cost price }} \times 100

25 =\frac{\text { (20-x) }}{\text { x }} \times 100

\frac{25x}{100}\ =\ 20\ -x

\frac{x}{4}\ =\ 20\ -x

x\ =\ 4\left(20\ -x\right)

x\ =\ 80\ -4x

5x\ =\ 80

x\ =\ \frac{80}{5}

x=16

The value of X is 16 units.

The profit or gain % is 5.45%.

Step by step Solution:

The cost price of an old scooter = Rs.4700

Repairing cost = Rs.800

Total cost of old scooter = Rs.4700+Rs.800=Rs.5500

The sale price of the scooter = Rs.5800

Sale Price > Cost Price

Profit = Sale Price – Cost Price = Rs.5800-Rs.5500=Rs.300

Profit% = 

Hence, the profit is 5.45%