TCS aptitude

A number is increased by 20% and then decreased by 20%. Find the net percentage change.

Let the original number be 100.

After 20% increase: 100 + 20 = 120
After 20% decrease: 120 - (20% of 120) = 120 - 24 = 96

Net change = 100 - 96 = 4
Net percentage change = (4/100) × 100 = 4% decrease

A shopkeeper marks his goods 20% above cost price but allows a discount of 10%. What is his profit percentage?

Let CP = ₹100
Marked Price (MP) = 100 + 20% of 100 = ₹120
Discount = 10% of 120 = ₹12
Selling Price (SP) = 120 - 12 = ₹108
Profit = 108 - 100 = ₹8
Profit % = (8/100) × 100 = 8%

A can complete a work in 12 days, B in 15 days, and C in 20 days. If they work together, in how many days will they complete the work?

Let total work = LCM of 12, 15, 20 = 60 units

A's efficiency = 60/12 = 5 units/day
B's efficiency = 60/15 = 4 units/day
C's efficiency = 60/20 = 3 units/day

Combined efficiency = 5 + 4 + 3 = 12 units/day
Time taken = 60/12 = 5 days

The ratio of ages of A and B is 3:5. After 8 years, the ratio becomes 5:7. Find the present age of A.

Let present ages be 3x and 5x.

After 8 years:

• A's age: 3x + 8
• B's age: 5x + 8

Given: (3x + 8)/(5x + 8) = 5/7

Cross-multiply:
7(3x + 8) = 5(5x + 8)
21x + 56 = 25x + 40
4x = 16
x = 4

Present age of A = 3x = 3 × 4 = 12 years

A sum of money amounts to ₹9800 after 5 years and ₹12005 after 8 years at the same rate of simple interest. Find the rate of interest per annum.

Let Principal = P, Rate = R%

After 5 years: P + (P × R × 5)/100 = 9800
After 8 years: P + (P × R × 8)/100 = 12005

Subtracting: (P × R × 3)/100 = 12005 - 9800 = 2205

P × R = 73500

From first equation: P + (73500 × 5)/100 = 9800
P + 3675 = 9800
P = 6125

Rate R = 73500/6125 = 12% per annum

Read the passage and answer: "Artificial Intelligence is transforming industries by automating processes and enabling data-driven decisions. However, concerns about job displacement and ethical implications remain significant." What is the main concern mentioned?

Answer: Job displacement and ethical implications

Explanation: The passage explicitly mentions concerns about job displacement and ethical implications as significant issues related to AI.

Identify the error: "Neither of the students were present in the class."

Error: "were" should be "was"

Correct Sentence: "Neither of the students was present in the class."

Explanation: "Neither" is singular and requires singular verb "was".

Find the synonym of "Benevolent".

Options:
A) Malevolent
B) Kind
C) Hostile
D) Cruel

Answer: B) Kind

Explanation: Benevolent means kind, generous, and well-meaning.

Statements: All cats are animals. Some animals are dogs. Conclusions: I. Some cats are dogs. II. All dogs are cats.

Analyzing the statements:

• All cats are animals (A → B)
• Some animals are dogs (B → C, some)

Conclusion I: Some cats are dogs

• Cannot be concluded. Some animals are dogs, but cats are a subset of animals. We cannot say some cats are dogs. Invalid

Conclusion II: All dogs are cats

• This cannot be concluded. Invalid

If "CAT" is coded as "3120", "DOG" is coded as "4157", then how is "RAT" coded?

Pattern analysis:

• C = 3, A = 1, T = 20 → "3120"
• D = 4, O = 15, G = 7 → "4157"

Pattern: Position of letter in alphabet

For "RAT":

• R = 18
• A = 1
• T = 20

Pointing to a man, a woman said, "His mother is the only daughter of my mother." How is the woman related to the man?

Let's break down the statement:

• "His mother" = the man's mother
• "only daughter of my mother" = the woman herself (since she's the only daughter)

So: The man's mother = the woman
Therefore, the woman is the mother of the man.

Find the next number in the series: 2, 6, 12, 20, 30, ?

Pattern analysis:

• 2 = 1 × 2
• 6 = 2 × 3
• 12 = 3 × 4
• 20 = 4 × 5
• 30 = 5 × 6

Next term = 6 × 7 = 42